mtd: spi-nor-core: Fix index value for SCCR dwords

Array index for SCCR 22th DWORD should be 21.

Fixes: bebdc237507c ("mtd: spi-nor: Parse SFDP SCCR Map")
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 44674cb..78de3c5 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -2520,7 +2520,7 @@
 	for (i = 0; i < sccr_header->length; i++)
 		table[i] = le32_to_cpu(table[i]);
 
-	if (FIELD_GET(SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE, table[22]))
+	if (FIELD_GET(SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE, table[21]))
 		nor->flags |= SNOR_F_IO_MODE_EN_VOLATILE;
 
 out: