misc: make the compiler happy...

The compiler treats uint8_t*[] and uint8_t* differently,
use the address of the first element and assign that.
diff --git a/openbsc/src/bts_siemens_bs11.c b/openbsc/src/bts_siemens_bs11.c
index 3d4ddda..0918693 100644
--- a/openbsc/src/bts_siemens_bs11.c
+++ b/openbsc/src/bts_siemens_bs11.c
@@ -62,7 +62,7 @@
 
 int bts_model_bs11_init(void)
 {
-	model_bs11.features.data = &model_bs11._features_data;
+	model_bs11.features.data = &model_bs11._features_data[0];
 	model_bs11.features.data_len = sizeof(model_bs11._features_data);
 
 	gsm_btsmodel_set_feature(&model_bs11, BTS_FEAT_HOPPING);