Prevent a seg-fault in the linker when trying to process SH object files with bogus...

Prevent a seg-fault in the linker when trying to process SH object files with bogus relocs.

	PR 22706
	* elf32-sh.c (sh_elf_relocate_section): When processing
	translation relocs, fail if the relocation offset is too small.
	Replace BFD_ASSERTs with more helpful error messages.