-Og warning fixes

-Og warning fixes

Found when building with gcc 4.9.4 using -Og.

bfd/
	* elf-eh-frame.c (offset_adjust): Avoid false positive gcc warning.
	* elflink.c (bfd_elf_size_dynsym_hash_dynstr): Likewise.
	* elfnn-aarch64.c (elfNN_aarch64_final_link_relocate): Likewise.
ld/
	* emultempl/msp430.em (eval_upper_either_sections): Make base_sec_name
	a const char*.
	(eval_lower_either_sections): Likewise.
	(msp430_elf_after_allocation): Likewise, and don't needlessly concat
	and free.  Warning fix.