[U-Boot] U-Boot build error when switch different SoC without clean

[Kever Yang]

Hi,

     I always met below error when build latest U-Boot for different board

and defconfig without "make clean", anyone know how to fix this?

   LD      lib/efi_loader/helloworld_efi.so
lib/efi_loader/efi_crt0.o: file not recognized: File format not recognized
   CC      lib/strto.o
scripts/Makefile.lib:394: recipe for target 
'lib/efi_loader/helloworld_efi.so' failed
make[2]: *** [lib/efi_loader/helloworld_efi.so] Error 1
scripts/Makefile.build:432: recipe for target 'lib/efi_loader' failed
make[1]: *** [lib/efi_loader] Error 2


Thanks,
- Kever