mtd: rawnand: omap2: Fix build warnings with W=1

Add kernel-doc for functions to get rid of below warnings
when built with W=1.

drivers/mtd/nand/raw/omap2.c:260: warning: Function parameter or struct member 'chip' not described in 'omap_nand_data_in_pref'
drivers/mtd/nand/raw/omap2.c:260: warning: Function parameter or struct member 'buf' not described in 'omap_nand_data_in_pref'
drivers/mtd/nand/raw/omap2.c:260: warning: Function parameter or struct member 'len' not described in 'omap_nand_data_in_pref'
drivers/mtd/nand/raw/omap2.c:260: warning: Function parameter or struct member 'force_8bit' not described in 'omap_nand_data_in_pref'
drivers/mtd/nand/raw/omap2.c:304: warning: Function parameter or struct member 'chip' not described in 'omap_nand_data_out_pref'
drivers/mtd/nand/raw/omap2.c:304: warning: Function parameter or struct member 'buf' not described in 'omap_nand_data_out_pref'
drivers/mtd/nand/raw/omap2.c:304: warning: Function parameter or struct member 'len' not described in 'omap_nand_data_out_pref'
drivers/mtd/nand/raw/omap2.c:304: warning: Function parameter or struct member 'force_8bit' not described in 'omap_nand_data_out_pref'
drivers/mtd/nand/raw/omap2.c:446: warning: Function parameter or struct member 'chip' not described in 'omap_nand_data_in_dma_pref'
drivers/mtd/nand/raw/omap2.c:446: warning: Function parameter or struct member 'buf' not described in 'omap_nand_data_in_dma_pref'
drivers/mtd/nand/raw/omap2.c:446: warning: Function parameter or struct member 'len' not described in 'omap_nand_data_in_dma_pref'
drivers/mtd/nand/raw/omap2.c:446: warning: Function parameter or struct member 'force_8bit' not described in 'omap_nand_data_in_dma_pref'
drivers/mtd/nand/raw/omap2.c:467: warning: Function parameter or struct member 'chip' not described in 'omap_nand_data_out_dma_pref'
drivers/mtd/nand/raw/omap2.c:467: warning: Function parameter or struct member 'buf' not described in 'omap_nand_data_out_dma_pref'
drivers/mtd/nand/raw/omap2.c:467: warning: Function parameter or struct member 'len' not described in 'omap_nand_data_out_dma_pref'
drivers/mtd/nand/raw/omap2.c:467: warning: Function parameter or struct member 'force_8bit' not described in 'omap_nand_data_out_dma_pref'

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202412031716.JfNIh1Uu-lkp@intel.com/
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Author: rogerq

drivers/mtd/nand/raw/omap2.c

@@ -254,6 +254,10 @@ static int omap_prefetch_reset(int cs, struct omap_nand_info *info)
 
 /**
  * omap_nand_data_in_pref - NAND data in using prefetch engine
+ * @chip: NAND chip
+ * @buf: output buffer where NAND data is placed into
+ * @len: length of transfer
+ * @force_8bit: force 8-bit transfers
  */
 static void omap_nand_data_in_pref(struct nand_chip *chip, void *buf,
 				   unsigned int len, bool force_8bit)
@@ -297,6 +301,10 @@ static void omap_nand_data_in_pref(struct nand_chip *chip, void *buf,
 
 /**
  * omap_nand_data_out_pref - NAND data out using Write Posting engine
+ * @chip: NAND chip
+ * @buf: input buffer that is sent to NAND
+ * @len: length of transfer
+ * @force_8bit: force 8-bit transfers
  */
 static void omap_nand_data_out_pref(struct nand_chip *chip,
 				    const void *buf, unsigned int len,
@@ -440,6 +448,10 @@ static inline int omap_nand_dma_transfer(struct nand_chip *chip,
 
 /**
  * omap_nand_data_in_dma_pref - NAND data in using DMA and Prefetch
+ * @chip: NAND chip
+ * @buf: output buffer where NAND data is placed into
+ * @len: length of transfer
+ * @force_8bit: force 8-bit transfers
  */
 static void omap_nand_data_in_dma_pref(struct nand_chip *chip, void *buf,
 				       unsigned int len, bool force_8bit)
@@ -460,6 +472,10 @@ static void omap_nand_data_in_dma_pref(struct nand_chip *chip, void *buf,
 
 /**
  * omap_nand_data_out_dma_pref - NAND data out using DMA and write posting
+ * @chip: NAND chip
+ * @buf: input buffer that is sent to NAND
+ * @len: length of transfer
+ * @force_8bit: force 8-bit transfers
  */
 static void omap_nand_data_out_dma_pref(struct nand_chip *chip,
 					const void *buf, unsigned int len,