py/mpconfig.h: Move PY_BUILTINS_POW3 config option to diff part of file.

With so many config options it's good to (at least try to) keep them
grouped into logical sections.

py/mpconfig.h

@@ -490,11 +490,6 @@
 #define MICROPY_LONGINT_IMPL (MICROPY_LONGINT_IMPL_NONE)
 #endif
 
-// Support for calls to pow() with 3 integer arguments
-#ifndef MICROPY_PY_BUILTINS_POW3
-#define MICROPY_PY_BUILTINS_POW3 (0)
-#endif
-
 #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_LONGLONG
 typedef long long mp_longint_impl_t;
 #endif
@@ -764,6 +759,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_BUILTINS_MIN_MAX (1)
 #endif
 
+// Support for calls to pow() with 3 integer arguments
+#ifndef MICROPY_PY_BUILTINS_POW3
+#define MICROPY_PY_BUILTINS_POW3 (0)
+#endif
+
 // Whether to provide the help function
 #ifndef MICROPY_PY_BUILTINS_HELP
 #define MICROPY_PY_BUILTINS_HELP (0)