[PSV] Update API to be able to use TargetCustom without UB.

getTargetCustom() requires values for "Kind" in the constructor
that are not in the PSVKind enum. Passing a value that is not inside
an enum as an argument to a constructor of the type of the enum is
UB. Changing to the underlying type of the enum would solve the UB

Differential Revision: https://reviews.llvm.org/D50909

llvm-svn: 340200
diff --git a/llvm/lib/Target/AMDGPU/R600InstrInfo.cpp b/llvm/lib/Target/AMDGPU/R600InstrInfo.cpp
index 5397e77..c54ea7a 100644
--- a/llvm/lib/Target/AMDGPU/R600InstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/R600InstrInfo.cpp
@@ -1500,7 +1500,7 @@
 }
 
 unsigned R600InstrInfo::getAddressSpaceForPseudoSourceKind(
-    PseudoSourceValue::PSVKind Kind) const {
+    unsigned Kind) const {
   switch (Kind) {
   case PseudoSourceValue::Stack:
   case PseudoSourceValue::FixedStack: