mtd: nand: do not check R/B# for CMD_READID in nand_command(_lp)

Read ID (0x90) command does not toggle the R/B# pin.  Without this
patch, NAND_CMD_READID falls into the default: label, then R/B# is
checked by chip->dev_ready().
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/nand_base.c

@@ -668,6 +668,7 @@ static void nand_command(struct mtd_info *mtd, unsigned int command,
 	case NAND_CMD_ERASE2:
 	case NAND_CMD_SEQIN:
 	case NAND_CMD_STATUS:
+	case NAND_CMD_READID:
 		return;
 
 	case NAND_CMD_RESET:
@@ -786,6 +787,7 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
 	case NAND_CMD_ERASE2:
 	case NAND_CMD_SEQIN:
 	case NAND_CMD_STATUS:
+	case NAND_CMD_READID:
 		return;
 
 	case NAND_CMD_RNDIN: