bts_feature: Introduce feature to confiure dyn ts as sdcch8

This feature signals support to configure Osmocom Dynamic Timeslot type
as SDCCH8, on top of historically supported TCH/H and TCH/F.
The idea is that when unneeded, the TS is configured as PDCH, and as
soon as there's need for an SDCCH and there's none available, the TS is
dynamically reconfigured to SDCCH8. Once all logical channels in the
dynamic TS are released and hence becomes free, the BSC will reconfigure
it to PDCH.

Related: SYS#5309
Change-Id: Ifc0ca8916bd3e93e5a60a7dd7391d2588fdb5532
diff --git a/src/gsm/bts_features.c b/src/gsm/bts_features.c
index 6671946..ecb5700 100644
--- a/src/gsm/bts_features.c
+++ b/src/gsm/bts_features.c
@@ -46,6 +46,7 @@
 	{ BTS_FEAT_VAMOS,		"VAMOS (Voice services over Adaptive Multi-user channels on One Slot)" },
 	{ BTS_FEAT_ABIS_OSMO_PCU,	"OsmoPCU over OML link IPA multiplex" },
 	{ BTS_FEAT_BCCH_POWER_RED,	"BCCH carrier power reduction mode" },
+	{ BTS_FEAT_DYN_TS_SDCCH8,	"Dynamic Timeslot configuration as SDCCH8" },
 	{ 0, NULL }
 };
 
@@ -79,5 +80,6 @@
 	{ BTS_FEAT_VAMOS, "VAMOS" },
 	{ BTS_FEAT_ABIS_OSMO_PCU, "ABIS_OSMO_PCU" },
 	{ BTS_FEAT_BCCH_POWER_RED, "BCCH_PWR_RED" },
+	{ BTS_FEAT_DYN_TS_SDCCH8, "DYN_TS_SDCCH8" },
 	{}
 };