bts/osmo-bsc.cfg: fix deprecated BTS type 'sysmobts'

Change-Id: If2f81141707e6f2360fc57bbd5f76606294f8db8
diff --git a/bts/osmo-bsc.cfg b/bts/osmo-bsc.cfg
index 1c8da8d..e4161fa 100644
--- a/bts/osmo-bsc.cfg
+++ b/bts/osmo-bsc.cfg
@@ -55,7 +55,7 @@
  handover1 maximum distance 9999
  timer t3212 30
  bts 0
-  type sysmobts
+  type osmo-bts
   band DCS1800
   cell_identity 0
   location_area_code 1