[clang] [Mips] Correctly define IntPtrType (PR #145158)

[Alex Rønne Petersen via cfe-commits]

alexrp wrote:

@hpoussin FWIW, since you have plenty of contributions already, you could go ahead and request commit access if you'd like: https://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access

https://github.com/llvm/llvm-project/pull/145158