mtd: nand: force NAND_CMD_READID onto 8-bit bus

The NAND command helpers tend to automatically shift the column address
for x16 bus devices, since most commands expect a word address, not a
byte address. The Read ID command, however, expects an 8-bit address
(i.e., 0x00, 0x20, or 0x40 should not be translated to 0x00, 0x10, or
0x20).

This fixes the column address for a few drivers which imitate the
nand_base defaults. Note that I don't touch sh_flctl.c, since it already
handles this problem slightly differently (note its comment "READID is
always performed using an 8-bit bus").

I have not tested this patch, as I only have x8 parts up for testing at
this point. Hopefully that can change soon...

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-By: Pekon Gupta <pekon@ti.com>

drivers/mtd/nand/diskonchip.c

@@ -698,7 +698,8 @@ static void doc2001plus_command(struct mtd_info *mtd, unsigned command, int colu
 		/* Serially input address */
 		if (column != -1) {
 			/* Adjust columns for 16 bit buswidth */
-			if (this->options & NAND_BUSWIDTH_16)
+			if (this->options & NAND_BUSWIDTH_16 &&
+					!nand_opcode_8bits(command))
 				column >>= 1;
 			WriteDOC(column, docptr, Mplus_FlashAddress);
 		}