bts/osmo-bts.cfg: use default {fn,rts}-advance values

It's better if we run ttcn3-bts-test with the default values, given
that they were significantly reduced some time ago.

Change-Id: Id97e848e5dfd0b6c504d06f62642511cfd5a0f66
Related: I7da3d0948f38e12342fb714b29f8edc5e9d0933d (osmo-bts)
Related: OS#4487
diff --git a/bts/osmo-bts.cfg b/bts/osmo-bts.cfg
index 1c83db7..4629180 100644
--- a/bts/osmo-bts.cfg
+++ b/bts/osmo-bts.cfg
@@ -34,8 +34,6 @@
 phy 0
  osmotrx ip local 127.0.0.1
  osmotrx ip remote 127.0.0.1
- osmotrx fn-advance 20
- osmotrx rts-advance 5
  instance 0
   osmotrx rx-gain 10
  instance 1