py/gc: Don't include mpconfig.h and misc.h in gc.h.

Because gc.h doesn't reference any symbol from these header files.

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

ports/esp8266/gccollect.c

@@ -26,6 +26,7 @@
 
 #include <stdio.h>
 
+#include "py/mpconfig.h"
 #include "py/gc.h"
 #include "gccollect.h"
 

py/gc.h

@@ -26,11 +26,9 @@
 #ifndef MICROPY_INCLUDED_PY_GC_H
 #define MICROPY_INCLUDED_PY_GC_H
 
+#include <stdbool.h>
 #include <stdint.h>
 
-#include "py/mpconfig.h"
-#include "py/misc.h"
-
 void gc_init(void *start, void *end);
 
 // These lock/unlock functions can be nested.