Add kMips and mips32r2 target attribute. Remove NoFramePointerElim.

MIPS ICS devices today are mips32r2. Tested LLVM on MIPS devices without
synci and rdhwr instructions to make sure LLVM/mips32r2 is working.

Change-Id: If1db7fe268e9f3b7d27eedbacd1d55620d57612a
diff --git a/src/compiler_llvm/utils_llvm.cc b/src/compiler_llvm/utils_llvm.cc
index a924793..405d7e2 100644
--- a/src/compiler_llvm/utils_llvm.cc
+++ b/src/compiler_llvm/utils_llvm.cc
@@ -161,7 +161,7 @@
     }
   }
 
-  CHECK(0) << "Error: Can't find symbol " << name;
+  LOG(FATAL) << "Error: Can't find symbol " << name;
   return 0;
 }