mtd: spi-nor-core: Add octal mode support

Add support for Octal flash devices. Octal flash devices use 8 IO lines
for data transfer. Currently only 1-1-8 Octal Read mode is supported.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
index 9208b16..4a02d95 100644
--- a/drivers/spi/spi-uclass.c
+++ b/drivers/spi/spi-uclass.c
@@ -461,6 +461,9 @@
 	case 4:
 		mode |= SPI_TX_QUAD;
 		break;
+	case 8:
+		mode |= SPI_TX_OCTAL;
+		break;
 	default:
 		warn_non_spl("spi-tx-bus-width %d not supported\n", value);
 		break;
@@ -476,6 +479,9 @@
 	case 4:
 		mode |= SPI_RX_QUAD;
 		break;
+	case 8:
+		mode |= SPI_RX_OCTAL;
+		break;
 	default:
 		warn_non_spl("spi-rx-bus-width %d not supported\n", value);
 		break;