* libpei.h (_bfd_XXi_final_link_postscript): Remove
duplication.
(bfd_target_pei_p): New.
(bfd_target_pei_arch): New
(bfd_target_efi_p): Likewise.
(bfd_target_efi_arch): New
(bfd_pe_executable_p): Use bfd_target_pei_p and
bfd_target_efi_p.
* peicode.h (arch_type): New enum.
(pe_arch): New function.
(pe_bfd_object_p): Don't match PE/EFI target with EFI/PE file
if there is an EFI/PE target.