vlr: remove unused parameter 'log_level' of auth_fsm_start()

We unconditionally use logging level of the parent FSM anyway.
All callers of auth_fsm_start() always pass fi->log_level.

Change-Id: If2fdf2564eb56d3d94ec3800bdcb0aabcad4e48d
diff --git a/src/libvlr/vlr_lu_fsm.c b/src/libvlr/vlr_lu_fsm.c
index e4d40f0..d5425e7 100644
--- a/src/libvlr/vlr_lu_fsm.c
+++ b/src/libvlr/vlr_lu_fsm.c
@@ -906,7 +906,7 @@
 		/* Authenticate_VLR */
 		osmo_fsm_inst_state_chg(fi, VLR_ULA_S_WAIT_AUTH,
 					LU_TIMEOUT_LONG, 0);
-		vsub->auth_fsm = auth_fsm_start(lfp->vsub, fi->log_level,
+		vsub->auth_fsm = auth_fsm_start(lfp->vsub,
 						fi, VLR_ULA_E_AUTH_RES,
 						lfp->is_r99,
 						lfp->is_utran);