subscr: Move the TMSI reserved into the gsm_data

Put it into the gsm_data.h to avoid requiring MSC code
in the BSC code paths.
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index 6131257..24aad88 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -68,6 +68,9 @@
 #define HARDCODED_BTS1_TS	6
 #define HARDCODED_BTS2_TS	11
 
+/* reserved according to GSM 03.03 § 2.4 */
+#define GSM_RESERVED_TMSI   0xFFFFFFFF
+
 enum gsm_hooks {
 	GSM_HOOK_NM_SWLOAD,
 	GSM_HOOK_RR_PAGING,
diff --git a/openbsc/include/openbsc/gsm_subscriber.h b/openbsc/include/openbsc/gsm_subscriber.h
index 02cab40..781629c 100644
--- a/openbsc/include/openbsc/gsm_subscriber.h
+++ b/openbsc/include/openbsc/gsm_subscriber.h
@@ -13,10 +13,6 @@
 #define GSM_MIN_EXTEN 20000
 #define GSM_MAX_EXTEN 49999
 
-/* reserved according to GSM 03.03 § 2.4 */
-#define GSM_RESERVED_TMSI   0xFFFFFFFF
-
-
 #define GSM_SUBSCRIBER_FIRST_CONTACT	0x00000001
 #define tmsi_from_string(str) strtoul(str, NULL, 10)