mtd: spi-nor: fsl-quadspi: fix unsupported cmd when run flash_erase

Erase function will use cmd 0x20 (SPINOR_OP_BE_4K) if kenrel enable option
CONFIG_MTD_SPI_NOR_USE_4K_SECTORS.

This command is not in fsl-quadspi driver LUT. So driver continue report
fsl-quadspi 21e0000.qspi: Unsupported cmd 0x20.

This patch fix this issue.
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Acked-by: Han Xu <Han.xu@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/spi-nor/fsl-quadspi.c

@@ -397,14 +397,8 @@ static void fsl_qspi_init_lut(struct fsl_qspi *q)
 	/* Erase a sector */
 	lut_base = SEQID_SE * 4;
 
-	if (q->nor_size <= SZ_16M) {
-		cmd = SPINOR_OP_SE;
-		addrlen = ADDR24BIT;
-	} else {
-		/* use the 4-byte address */
-		cmd = SPINOR_OP_SE;
-		addrlen = ADDR32BIT;
-	}
+	cmd = q->nor[0].erase_opcode;
+	addrlen = q->nor_size <= SZ_16M ? ADDR24BIT : ADDR32BIT;
 
 	writel(LUT0(CMD, PAD1, cmd) | LUT1(ADDR, PAD1, addrlen),
 			base + QUADSPI_LUT(lut_base));
@@ -473,6 +467,8 @@ static int fsl_qspi_get_seqid(struct fsl_qspi *q, u8 cmd)
 	case SPINOR_OP_BRWR:
 		return SEQID_BRWR;
 	default:
+		if (cmd == q->nor[0].erase_opcode)
+			return SEQID_SE;
 		dev_err(q->dev, "Unsupported cmd 0x%.2x\n", cmd);
 		break;
 	}