am 5e12e60b: Merge "For the current MIPS compiler __builtin___clear_cache() generates synci instruction only with -msynci option So, add -msynci to all mips32r2 makefiles. Also add msynci to the list flags not recognized by clang."

* commit '5e12e60b472fbd2e712ee9ba04637e3d26b18b71':
  For the current MIPS compiler __builtin___clear_cache() generates synci instruction only with -msynci option So, add -msynci to all mips32r2 makefiles. Also add msynci to the list flags not recognized by clang.