[mips] Use __clear_cache builtin instead of cacheflush() in Unix Memory::InvalidateInstructionCache()

MIPS64 Android bionic has removed cacheflush(). Use __clear_cache() instead for 32-bit and 64-bit MIPS

Patch by Duane Sand <Duane.Sand@imgtec.com>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211588 91177308-0d34-0410-b5e6-96231b3b80d8