Refine MMI & MSA detection for mips

Refine MMI & MSA detection for mips

1.Add compile check to probe the native ability of
toolchain to decide whether a feature can be enabled.
2.Add runtime check to probe cpu supported features.
MSA will be prefered if MSA and MMI are both supported.
3.You can configure and build as following commands:
./configure --cpu=loongson3a && make -j4

Change-Id: I057553216dbc79cfaba9c691d5f4cdab144e1123