[LLDB][MIPS] Provide ABI string to compiler for appropriate code generation for MIPS

Patch by Nitesh Jain.

Summary: These patch will set clang::TargetOptions::ABI and accordingly code will be generated for MIPS target.

Reviewers: ovyalov, clayborg
Subscribers: lldb-commits, mohit.bhakkad, sagar, jaydeep, bhushan
Differential: D18638
llvm-svn: 269407