mvebu: support UART boot image

The kwboot utility can use the generated image to boot mvebu SoCs from
UART.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Stefan Roese <sr@denx.de>

arch/arm/mach-mvebu/Kconfig

@@ -193,6 +193,9 @@ config MVEBU_SPL_BOOT_DEVICE_MMC
 	bool "SDIO/MMC card"
 	select SPL_LIBDISK_SUPPORT
 
+config MVEBU_SPL_BOOT_DEVICE_UART
+	bool "UART"
+
 endchoice
 
 config MVEBU_EFUSE

arch/arm/mach-mvebu/Makefile

@@ -35,6 +35,9 @@ endif
 ifneq ($(CONFIG_MVEBU_SPL_BOOT_DEVICE_MMC),)
 	KWB_CFG_BOOT_FROM=sdio
 endif
+ifneq ($(CONFIG_MVEBU_SPL_BOOT_DEVICE_UART),)
+	KWB_CFG_BOOT_FROM=uart
+endif
 
 ifneq ($(CONFIG_SECURED_MODE_IMAGE),)
 KWB_REPLACE += CSK_INDEX