uboot-imx

efi_loader: disconnect controllers in UninstallProtocol

The UninstallProtocol boot service should first try to
disconnect controllers that have been connected with
EFI_OPEN_PROTOCOL_BY_DRIVER.

If the protocol is still opened by an agent, it should be
closed.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>