[HSL] initial support for the HSL 2.75G Femtocell

The HSL Femtocell seems to be a poor man implementation of the
ip.access Abis/IP protocol, but cutting corners wherever possible.

We try to workaround those corners wherever possible...
diff --git a/openbsc/src/libcommon/gsm_data.c b/openbsc/src/libcommon/gsm_data.c
index f181fd1..b2c52e4 100644
--- a/openbsc/src/libcommon/gsm_data.c
+++ b/openbsc/src/libcommon/gsm_data.c
@@ -416,6 +416,7 @@
 	{ GSM_BTS_TYPE_BS11,	"bs11" },
 	{ GSM_BTS_TYPE_NANOBTS,	"nanobts" },
 	{ GSM_BTS_TYPE_RBS2000,	"rbs2000" },
+	{ GSM_BTS_TYPE_HSL_FEMTO, "hsl_femto" },
 	{ 0,			NULL }
 };
 
@@ -571,6 +572,8 @@
 	bts->model = model;
 
 	switch (bts->type) {
+	case GSM_BTS_TYPE_HSL_FEMTO:
+		bts->c0->rsl_tei = 0;
 	case GSM_BTS_TYPE_NANOBTS:
 		/* Set the default OML Stream ID to 0xff */
 		bts->oml_tei = 0xff;