Trigger PACCH assignment inside dl_tbf_upgrade_to_multislot()

The triggering of the assignment for the new TBF allocation is part of
the "upgrade to multislot" process, hence move that inside the function.

Change-Id: Ic2b959f2476b900cb263ccd8f6698ed843bafd29
diff --git a/src/tbf_dl_fsm.c b/src/tbf_dl_fsm.c
index 0ab740d..7d1f9b1 100644
--- a/src/tbf_dl_fsm.c
+++ b/src/tbf_dl_fsm.c
@@ -345,11 +345,8 @@
 	ctx->state_flags &= GPRS_RLCMAC_FLAG_TO_MASK;
 
 	rc = dl_tbf_upgrade_to_multislot(ctx->dl_tbf);
-	if (rc < 0) {
+	if (rc < 0)
 		tbf_free(ctx->tbf);
-		return;
-	}
-	dl_tbf_trigger_ass_on_pacch(ctx->dl_tbf, ctx->tbf);
 }
 
 static int tbf_dl_fsm_timer_cb(struct osmo_fsm_inst *fi)