spi: cadence: Fix busy cycles calculation

If xSPI is in x2/x4/x8 mode to calculate busy
cycles, busy bits count must be divided by the number
of lanes.
If opcommand is using 8 busy bits, but SPI is
in x4 mode, there will be only 2 busy cycles.

Signed-off-by: Witold Sadowski <wsadowski@marvell.com>
Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Link: https://lore.kernel.org/r/20221219144254.20883-2-wsadowski@marvell.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Witold Sadowski

drivers/spi/spi-cadence-xspi.c

@@ -177,7 +177,10 @@
 #define CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op) ( \
 	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_DCNT_H, \
 		((op)->data.nbytes >> 16) & 0xffff) | \
-	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, (op)->dummy.nbytes * 8))
+	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, \
+		  (op)->dummy.buswidth != 0 ? \
+		  (((op)->dummy.nbytes * 8) / (op)->dummy.buswidth) : \
+		  0))
 
 #define CDNS_XSPI_CMD_FLD_DSEQ_CMD_4(op, chipsel) ( \
 	FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R4_BANK, chipsel) | \