spi: dw: Convert to using BITS_TO_BYTES() macro

Since commit dd3e7cb ("ocfs2/dlm: move BITS_TO_BYTES() to bitops.h
for wider use") there is a generic helper available to calculate a number
of bytes needed to accommodate the specified number of bits. Let's use it
instead of the hard-coded DIV_ROUND_UP() macro function.

Signed-off-by: Serge Semin <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

drivers/spi/spi-dw-core.c

@@ -6,6 +6,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/bitops.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
@@ -421,10 +422,7 @@ static int dw_spi_transfer_one(struct spi_controller *host,
 	int ret;
 
 	dws->dma_mapped = 0;
-	dws->n_bytes =
-		roundup_pow_of_two(DIV_ROUND_UP(transfer->bits_per_word,
-						BITS_PER_BYTE));
-
+	dws->n_bytes = roundup_pow_of_two(BITS_TO_BYTES(transfer->bits_per_word));
 	dws->tx = (void *)transfer->tx_buf;
 	dws->tx_len = transfer->len / dws->n_bytes;
 	dws->rx = transfer->rx_buf;