[NFC][SPIRV] Remove useless static_cast (llvm#164239)

Author: jmmartinez

llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp

@@ -547,9 +547,9 @@ void SPIRVModuleAnalysis::collectFuncNames(MachineInstr &MI,
   if (MI.getOpcode() == SPIRV::OpDecorate) {
     // If it's got Import linkage.
     auto Dec = MI.getOperand(1).getImm();
-    if (Dec == static_cast<unsigned>(SPIRV::Decoration::LinkageAttributes)) {
+    if (Dec == SPIRV::Decoration::LinkageAttributes) {
       auto Lnk = MI.getOperand(MI.getNumOperands() - 1).getImm();
-      if (Lnk == static_cast<unsigned>(SPIRV::LinkageType::Import)) {
+      if (Lnk == SPIRV::LinkageType::Import) {
         // Map imported function name to function ID register.
         const Function *ImportedFunc =
             F->getParent()->getFunction(getStringImm(MI, 2));