py/vm: Adjust #if logic for gil_divisor so braces are balanced.

Having balanced braces { and } makes it easier to navigate the function.

py/vm.c

@@ -1322,11 +1322,12 @@ pending_exception_check:
 
                 #if MICROPY_PY_THREAD_GIL
                 #if MICROPY_PY_THREAD_GIL_VM_DIVISOR
-                if (--gil_divisor == 0) {
-                    gil_divisor = MICROPY_PY_THREAD_GIL_VM_DIVISOR;
-                #else
-                {
+                if (--gil_divisor == 0)
                 #endif
+                {
+                    #if MICROPY_PY_THREAD_GIL_VM_DIVISOR
+                    gil_divisor = MICROPY_PY_THREAD_GIL_VM_DIVISOR;
+                    #endif
                     #if MICROPY_ENABLE_SCHEDULER
                     // can only switch threads if the scheduler is unlocked
                     if (MP_STATE_VM(sched_state) == MP_SCHED_IDLE)