resolve this compile warning hinting about bad code:

msgb/msgb_test.c:198:31: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
   msgb_resize_area(msg, NULL, (int)msg->data, 0);

---
 tests/msgb/msgb_test.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: libosmocore/tests/msgb/msgb_test.c
===================================================================
--- libosmocore.orig/tests/msgb/msgb_test.c
+++ libosmocore/tests/msgb/msgb_test.c
@@ -195,7 +195,7 @@ static void test_msgb_resize_area()
 	OSMO_ASSERT(e != 0);
 
 	if (OSMO_PANIC_TRY(&e))
-		msgb_resize_area(msg, NULL, (int)msg->data, 0);
+		msgb_resize_area(msg, NULL, (intptr_t)msg->data, 0);
 	OSMO_ASSERT(e != 0);
 
 	if (OSMO_PANIC_TRY(&e))