[mips] Fix 'l' constraint handling for types smaller than 32 bits

In case of correct using of the 'l' constraint llvm now generates valid
code; otherwise it shows an error message. Initially these triggers an
assertion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324869 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed