bfd_reloc_offset_in_range overflow

bfd_reloc_offset_in_range overflow

This patch is more about the style of bounds checking we ought to use,
rather than a real problem.  An overflow of "octet + reloc_size" can
only happen with huge sections which would certainly cause out of
memory errors.

	* reloc.c (bfd_reloc_offset_in_range): Avoid possible overflow.