bfd/ELF: restrict file alignment for object files

bfd/ELF: restrict file alignment for object files

While for executables properly aligning sections within the file can be
quite relevant, the same is of pretty little importance for relocatable
object files. Avoid passing "true" into
_bfd_elf_assign_file_position_for_section() when dealing with object
files, but compensate minimally by applying log_file_align in such
cases as a cap to the alignment put in place.