efi_loader: clean up UEFI sub-system initialization

allow_unaligned(), switch_to_non_secure_mode(), and efi_init_obj_list() are
called in sequence in multiple places.

Move calls to allow_unaligned() and switch_to_non_secure_mode() to
efi_init_obj_list().

Remove unused includes.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>