mtd: rawnand: meson: fix bitmask for length in command word

Valid mask is 0x3FFF, without this patch the following problems were
found:

1) [    0.938914] Could not find a valid ONFI parameter page, trying
                  bit-wise majority to recover it
   [    0.947384] ONFI parameter recovery failed, aborting

2) Read with disabled ECC mode was broken.

Fixes: 8fae856 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/3794ffbf-dfea-e96f-1f97-fe235b005e19@sberdevices.ru

Author: Arseniy Krasnov

drivers/mtd/nand/raw/meson_nand.c

@@ -280,7 +280,7 @@ static void meson_nfc_cmd_access(struct nand_chip *nand, int raw, bool dir,
 
 	if (raw) {
 		len = mtd->writesize + mtd->oobsize;
-		cmd = (len & GENMASK(5, 0)) | scrambler | DMA_DIR(dir);
+		cmd = (len & GENMASK(13, 0)) | scrambler | DMA_DIR(dir);
 		writel(cmd, nfc->reg_base + NFC_REG_CMD);
 		return;
 	}
@@ -544,7 +544,7 @@ static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
 	if (ret)
 		goto out;
 
-	cmd = NFC_CMD_N2M | (len & GENMASK(5, 0));
+	cmd = NFC_CMD_N2M | (len & GENMASK(13, 0));
 	writel(cmd, nfc->reg_base + NFC_REG_CMD);
 
 	meson_nfc_drain_cmd(nfc);
@@ -568,7 +568,7 @@ static int meson_nfc_write_buf(struct nand_chip *nand, u8 *buf, int len)
 	if (ret)
 		return ret;
 
-	cmd = NFC_CMD_M2N | (len & GENMASK(5, 0));
+	cmd = NFC_CMD_M2N | (len & GENMASK(13, 0));
 	writel(cmd, nfc->reg_base + NFC_REG_CMD);
 
 	meson_nfc_drain_cmd(nfc);