abis_rsl: The rach information was not used, introduce a signal

Introduce a SS_CCCH for the paging and the rach load. The paging
code could now start using the signal.

GCC warning:
abis_rsl.c: In function ‘rsl_rx_ccch_load’:
abis_rsl.c:1371:11: warning: variable ‘rach_access_count’ set but not used [-Wunused-but-set-variable]
abis_rsl.c:1370:11: warning: variable ‘rach_busy_count’ set but not used [-Wunused-but-set-variable]
abis_rsl.c:1369:11: warning: variable ‘rach_slot_count’ set but not used [-Wunused-but-set-variable]
diff --git a/openbsc/include/openbsc/signal.h b/openbsc/include/openbsc/signal.h
index 7f30f4f..f96c5e3 100644
--- a/openbsc/include/openbsc/signal.h
+++ b/openbsc/include/openbsc/signal.h
@@ -46,6 +46,7 @@
 	SS_RF,
 	SS_MSC,
 	SS_HO,
+	SS_CCCH,
 };
 
 /* SS_PAGING signals */
@@ -247,4 +248,18 @@
 	struct gsm_lchan *new_lchan;
 };
 
+/* SS_CCCH signals */
+enum signal_ccch {
+	S_CCCH_PAGING_LOAD,
+	S_CCCH_RACH_LOAD,
+};
+
+struct ccch_signal_data {
+	struct gsm_bts *bts;
+	uint16_t pg_buf_space;
+	uint16_t rach_slot_count;
+	uint16_t rach_busy_count;
+	uint16_t rach_access_count;
+};
+
 #endif