uboot-phytec

efi_loader: Add exit support

Some times you may want to exit an EFI payload again, for example
to default boot into a PXE installation and decide that you would
rather want to boot from the local disk instead.

This patch adds exit functionality to the EFI implementation, allowing
EFI payloads to exit.

Signed-off-by: Alexander Graf <agraf@suse.de>