Fix test build breakage when not compiling with mesh support

Build breakage was introduced by commit
16579769ff7bb255e101c6b77fb2c47d3735a883 ('Add testing functionality for
resetting PN/IPN for configured keys') for some CONFIG_TESTING_OPTIONS=y
builds.

Signed-off-by: Ben Greear <greearb@candelatech.com>

src/ap/sta_info.h

@@ -9,11 +9,7 @@
 #ifndef STA_INFO_H
 #define STA_INFO_H
 
-#ifdef CONFIG_MESH
-/* needed for mesh_plink_state enum */
 #include "common/defs.h"
-#endif /* CONFIG_MESH */
-
 #include "list.h"
 #include "vlan.h"
 #include "common/wpa_common.h"