[mips] Check argument for __builtin_msa_ctcmsa / __builtin_msa_cfcmsa

[mips] Check argument for __builtin_msa_ctcmsa / __builtin_msa_cfcmsa

The `__builtin_msa_ctcmsa` and `__builtin_msa_cfcmsa` builtins are mapped
to the `ctcmsa` and `cfcmsa` instructions respectively. While MSA
control registers have indexes in 0..7 range, the instructions accept
register index in 0..31 range [1].

[1] MIPS Architecture for Programmers Volume IV-j:
    The MIPS64 SIMD Architecture Module
https://www.mips.com/?do-download=the-mips64-simd-architecture-module

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@361967 91177308-0d34-0410-b5e6-96231b3b80d8