[mips] [IAS] Remove AssemblerPredicate's from RelocPIC and RelocStatic.

Summary:
These AssemblerPredicate's are unnecessary and actually make some instructions unusable when assembling pre-MIPS32 ISAs.
For example, this was causing the IAS to reject the 'j' instruction for MIPS I-V.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8300

llvm-svn: 234398