no need to make gsmnet structure non-static (fix from last commit)

diff --git a/src/bsc_hack.c b/src/bsc_hack.c
index 346247c..fb76233 100644
--- a/src/bsc_hack.c
+++ b/src/bsc_hack.c
@@ -48,7 +48,7 @@
 #include <openbsc/e1_input.h>
 
 /* global pointer to the gsm network data structure */
-struct gsm_network *gsmnet;
+static struct gsm_network *gsmnet;
 
 /* MCC and MNC for the Location Area Identifier */
 static int MCC = 1;