[Mips] Silencing warnings in instruction info (NFC)

isORCopyInst and isReadOrWriteToDSPReg functions were producing warning
that some statements my fall through.

Patch by Nikola Prica.

Differential Revision: https://reviews.llvm.org/D47876


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334194 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed