mtd: nand: denali: correct buffer alignment for DMA transfer

The NAND framework makes sure to pass in the buffer with at least
chip->buf_align alignment.  Currently, the Denali NAND driver only
requests 16 byte alignment.  This causes unaligned cache operations
for the DMA transfer.

[Error Example]

=> nand read 81000010 0 1000

NAND read: device 0 offset 0x0, size 0x1000
CACHE: Misaligned operation at range [81000010, 81001010]
CACHE: Misaligned operation at range [81000010, 81001010]
CACHE: Misaligned operation at range [81000010, 81001010]
CACHE: Misaligned operation at range [81000010, 81001010]
 4096 bytes read: OK

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/mtd/nand/denali.c

@@ -1270,7 +1270,7 @@ int denali_init(struct denali_nand_info *denali)
 		denali->dma_avail = 1;
 
 	if (denali->dma_avail) {
-		chip->buf_align = 16;
+		chip->buf_align = ARCH_DMA_MINALIGN;
 		if (denali->caps & DENALI_CAP_DMA_64BIT)
 			denali->setup_dma = denali_setup_dma64;
 		else