qcacmn: Fix compilation error in interface manager

- Compiler does not find declaration for functions
  declared in wlan_objmgr_global_obj.h file,
  causing errors fix is to add include header file.

Change-Id: I5cd7f8ed78f36444d9512d5fecec62ad7d1cadde
CRs-Fixed: 2779850

umac/cmn_services/interface_mgr/src/wlan_if_mgr_main.c

@@ -18,6 +18,7 @@
  * DOC: contains core interface manager function definitions
  */
 #include "wlan_if_mgr_main.h"
+#include "wlan_objmgr_global_obj.h"
 
 QDF_STATUS wlan_if_mgr_init(void)
 {