configs: dra7xx: Update QSPI speed to 76.8MHz

Now that QSPI driver can support 76.8MHz, update the
CONFIG_SF_DEFAULT_SPEED to the same value.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
diff --git a/include/configs/dra7xx_evm.h b/include/configs/dra7xx_evm.h
index 0d51aeb..0b78ada 100644
--- a/include/configs/dra7xx_evm.h
+++ b/include/configs/dra7xx_evm.h
@@ -157,7 +157,7 @@
 /* SPI */
 #undef	CONFIG_OMAP3_SPI
 #define CONFIG_TI_SPI_MMAP
-#define CONFIG_SF_DEFAULT_SPEED                64000000
+#define CONFIG_SF_DEFAULT_SPEED                76800000
 #define CONFIG_SF_DEFAULT_MODE                 SPI_MODE_0
 #define CONFIG_QSPI_QUAD_SUPPORT