sifive: fu540: Add Booting from SPI

Add booting from SPI for SiFive Unleashed board.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Tested-by: Bin Meng <bin.meng@windriver.com>
diff --git a/configs/sifive_fu540_defconfig b/configs/sifive_fu540_defconfig
index 9e00a56..06e1786 100644
--- a/configs/sifive_fu540_defconfig
+++ b/configs/sifive_fu540_defconfig
@@ -6,6 +6,7 @@
 CONFIG_SPL_MMC_SUPPORT=y
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_SPL=y
+CONFIG_SPL_SPI_FLASH_SUPPORT=y
 CONFIG_SPL_SPI_SUPPORT=y
 CONFIG_TARGET_SIFIVE_FU540=y
 CONFIG_ARCH_RV64I=y
@@ -16,8 +17,11 @@
 CONFIG_DISPLAY_CPUINFO=y
 CONFIG_DISPLAY_BOARDINFO=y
 CONFIG_SPL_SEPARATE_BSS=y
+CONFIG_SPL_DM_SPI_FLASH=y
+CONFIG_SPL_SPI_LOAD=y
 CONFIG_SPL_YMODEM_SUPPORT=y
 CONFIG_DEFAULT_DEVICE_TREE="hifive-unleashed-a00"
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_SPL_DM_SEQ_ALIAS=y
 CONFIG_SPL_CLK=y
 CONFIG_DM_MTD=y