mtd: spi-nor: Fix errno on Quad Enable methods

When the Read-Modify-Write-Read-Back Quad Enable methods failed on
the Read-Back, they returned -EINVAL. Since this is an I/O error,
return -EIO.
Signed-off-by: NTudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: NVignesh Raghavendra <vigneshr@ti.com>

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

@@ -1964,7 +1964,7 @@ static int macronix_quad_enable(struct spi_nor *nor)
 
 	if (!(nor->bouncebuf[0] & SR_QUAD_EN_MX)) {
 		dev_dbg(nor->dev, "Macronix Quad bit not set\n");
-		return -EINVAL;
+		return -EIO;
 	}
 
 	return 0;
@@ -2042,7 +2042,7 @@ static int spansion_read_cr_quad_enable(struct spi_nor *nor)
 
 	if (!(sr_cr[1] & CR_QUAD_EN_SPAN)) {
 		dev_dbg(nor->dev, "Spansion Quad bit not set\n");
-		return -EINVAL;
+		return -EIO;
 	}
 
 	return 0;
@@ -2086,7 +2086,7 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
 
 	if (!(*sr2 & SR2_QUAD_EN_BIT7)) {
 		dev_dbg(nor->dev, "SR2 Quad bit not set\n");
-		return -EINVAL;
+		return -EIO;
 	}
 
 	return 0;