[NVPTX] Fix logic error in loading vector parameters of more than 4 components

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194409 91177308-0d34-0410-b5e6-96231b3b80d8
[NVPTX] Properly handle bitcast ConstantExpr when checking for the alignment of function parameters

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194410 91177308-0d34-0410-b5e6-96231b3b80d8