rlc: Add decode_gsm_ra_cap to decode Radio Access Caps

This uses the CSN.1 decoder to fully parse the radio access
capabilities as defined by TS 24.008, 10.5.5.12a.

Sponsored-by: On-Waves ehf
diff --git a/src/gsm_rlcmac.cpp b/src/gsm_rlcmac.cpp
index 44bc5e1..6b43aa6 100644
--- a/src/gsm_rlcmac.cpp
+++ b/src/gsm_rlcmac.cpp
@@ -5509,3 +5509,11 @@
     LOGPC(DRLCMACDATA, LOGL_NOTICE, "\n");
   }
 }
+
+void decode_gsm_ra_cap(bitvec * vector, MS_Radio_Access_capability_t *data)
+{
+  csnStream_t      ar;
+  unsigned readIndex = 0;
+  csnStreamInit(&ar, 0, 8 * vector->data_len);
+  /*ret =*/ csnStreamDecoder(&ar, CSNDESCR(MS_Radio_Access_capability_t), vector, readIndex, data);
+}