arm: mvebu: Implement return_to_bootrom() via U-Boot's SPL framework

U-Boot's SPL framework already has an API for loading U-Boot via
BootROM.

Implement the function board_return_to_bootrom() for mvebu SPL code.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Chris Packham <judge.packham@gmail.com>
Tested-by: Chris Packham <judge.packham@gmail.com>
diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index 27d227d..12de6f1 100644
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -257,6 +257,7 @@
 	select SPL_SPI_FLASH_SUPPORT
 	select SPL_SPI_LOAD
 	select SPL_SPI_SUPPORT
+	select SPL_BOOTROM_SUPPORT
 
 config MVEBU_SPL_BOOT_DEVICE_MMC
 	bool "SDIO/MMC card"
@@ -267,14 +268,17 @@
 	select SPL_GPIO
 	select SPL_LIBDISK_SUPPORT
 	select SPL_MMC_SUPPORT
+	select SPL_BOOTROM_SUPPORT
 
 config MVEBU_SPL_BOOT_DEVICE_SATA
 	bool "SATA"
 	select SPL_SATA_SUPPORT
 	select SPL_LIBDISK_SUPPORT
+	select SPL_BOOTROM_SUPPORT
 
 config MVEBU_SPL_BOOT_DEVICE_UART
 	bool "UART"
+	select SPL_BOOTROM_SUPPORT
 
 endchoice