[lldb-server][MIPS] Read/Write FP registers in FR0 mode

    Adding support for read/write FP registers in FR0 mode of mips.

Reviewers: clayborg, tberghammer, jaydeep
Subscribers: emaste, nitesh.jain, bhushan, mohit.bhakkad, lldb-commits
Differential Revision: http://reviews.llvm.org/D10242

llvm-svn: 239132