[mlir][emitc] Delete unused function 'isSwitchOperandType'

Author: EtoAndruwa

mlir/lib/Dialect/EmitC/IR/EmitC.cpp

@@ -131,11 +131,6 @@ bool mlir::emitc::isPointerWideType(Type type) {
       type);
 }
 
-bool mlir::emitc::isSwitchOperandType(Type type) {
-  return isa<emitc::OpaqueType, IndexType>(type) ||
-         isSupportedIntegerType(type);
-}
-
 /// Check that the type of the initial value is compatible with the operations
 /// result type.
 static LogicalResult verifyInitializationAttribute(Operation *op,