all: Format code to add space after C++-style comment start.

Note: the uncrustify configuration is explicitly set to 'add' instead of
'force' in order not to alter the comments which use extra spaces after //
as a means of indenting text for clarity.

mpy-cross/gccollect.c

@@ -146,4 +146,4 @@ void gc_collect(void) {
     gc_collect_end();
 }
 
-#endif //MICROPY_ENABLE_GC
+#endif // MICROPY_ENABLE_GC

mpy-cross/mpconfigport.h

@@ -141,7 +141,7 @@ typedef long mp_off_t;
 #else
 #define MP_SSIZE_MAX                _I32_MAX
 #endif
-#define MICROPY_MAKE_POINTER_CALLABLE(p) ((void *)(p)) //Avoid compiler warning about different const qualifiers
+#define MICROPY_MAKE_POINTER_CALLABLE(p) ((void *)(p)) // Avoid compiler warning about different const qualifiers
 #define restrict
 #define inline                      __inline
 #define alignof(t)                  __alignof(t)