[GPRS] introudce PDCH and PDCH/TCH physical channels

GPRS needs PDCH (Packet Data Channels), and we need support in
our data model as well as OML and RSL for it
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index d04b0c7..9a277ae 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -18,6 +18,8 @@
 	GSM_PCHAN_TCH_F,
 	GSM_PCHAN_TCH_H,
 	GSM_PCHAN_SDCCH8_SACCH8C,
+	GSM_PCHAN_PDCH,		/* GPRS PDCH */
+	GSM_PCHAN_TCH_F_PDCH,	/* TCH/F if used, PDCH otherwise */
 	GSM_PCHAN_UNKNOWN,
 };