efi_loader: always rebuild efi_crt0.o

When changing the architecture without calling 'make clean' a subsequent
make fails with
lib/efi_loader/efi_crt0.o: file not recognized: File format not recognized

Force efi_crt0.o to be always rebuild.
Reported-by: NKever Yang <kever.yang@rock-chips.com>
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>

scripts/Makefile.lib

@@ -383,7 +383,7 @@ cmd_efi_ld = $(LD) -nostdlib -znocombreloc -T $(EFI_LDS_PATH) -shared \
 
 EFI_LDS_PATH = $(srctree)/arch/$(ARCH)/lib/$(EFI_LDS)
 
-$(obj)/efi_crt0.o: $(srctree)/arch/$(ARCH)/lib/$(EFI_CRT0:.o=.S)
+$(obj)/efi_crt0.o: $(srctree)/arch/$(ARCH)/lib/$(EFI_CRT0:.o=.S) FORCE
 	$(call if_changed_dep,as_o_S)
 
 $(obj)/efi_reloc.o: $(srctree)/arch/$(ARCH)/lib/$(EFI_RELOC:.o=.c) $(recordmcount_source) FORCE