Fix a bug in resolving HI16/LO16 relocation pairs for MIPS.

Fix a bug in resolving HI16/LO16 relocation pairs for MIPS.

2015-01-14  Sasa Stankovic  <Sasa.Stankovic@imgtec.com>

gold/
	* mips.cc (reloc_high): Add r_sym.
	(Mips_relocate_functions::relhi16): Add r_sym parameter. Pass r_sym to
	reloc_high constructor.
	(Mips_relocate_functions::relgot16_local): Likewise.
	(Mips_relocate_functions::rello16): Add r_sym parameter. Use r_sym and
	r_type to decide whether LO16 matches HI16.
	(Target_mips::Relocate::relocate): Pass r_sym to calls to relhi16,
	rello16 and relgot16_local.