Try fix mypy no-redef error

src/pystencils/backend/platforms/generic_cpu.py

@@ -63,12 +63,12 @@ class GenericCpu(Platform):
         arg_types = (dtype,) * func.num_args
 
         if isinstance(dtype, PsScalarType) and func in (NumericLimitsFunctions.Min, NumericLimitsFunctions.Max):
+            cfunc: CFunction
             cfunc = CFunction(f"{dtype.c_string()}_{func.function_name}".capitalize(), arg_types, dtype)
             call.function = cfunc
             return call
 
         if isinstance(dtype, PsIeeeFloatType) and dtype.width in (32, 64):
-            cfunc: CFunction
             match func:
                 case (
                     MathFunctions.Exp