Mips: Add ImmArg to intrinsics

Mips: Add ImmArg to intrinsics

I found these by asserting in clang for any GCCBuiltin that doesn't
require mangling and requires a constant for the builtin. This means
that intrinsics are missing which don't use GCCBuiltin, don't have
builtins defined in clang, or were missing the constant annotation in
the builtin definition.

I'm not sure what's going on with the immediates.ll test. It seems to
be intended to test invalid cases like this, but then tries to handle
some of them anyway. I've moved the cases that were inconsistent with
the GCCBuiltin definition so they don't test the codegen anymore.

llvm-svn: 356085