dyn TS: rename lchan->dyn_pdch to lchan->dyn

This will also be used by the new dynamic TS type, so make the name more
general.

Change-Id: I2451b10519dff3e5cdf503b430574c0984d19000
diff --git a/openbsc/include/openbsc/gsm_data_shared.h b/openbsc/include/openbsc/gsm_data_shared.h
index 7036619..f4da7a7 100644
--- a/openbsc/include/openbsc/gsm_data_shared.h
+++ b/openbsc/include/openbsc/gsm_data_shared.h
@@ -261,7 +261,7 @@
 		/* channel activation type and handover ref */
 		uint8_t act_type;
 		uint8_t ho_ref;
-	} dyn_pdch;
+	} dyn;
 #else
 	/* Number of different GsmL1_Sapi_t used in osmo_bts_sysmo is 23.
 	 * Currently we don't share these headers so this is a magic number. */