Drop unneeded arg 'ta' in tbf_alloc_ul()

The function is simply setting the ta on the ms, so simply make sure ta
is set on callers before passing the ms object.

Change-Id: Iebb9c57f458690e045ddc45c800209ad8cf621e0
diff --git a/src/tbf.cpp b/src/tbf.cpp
index 56fdcd1..2693223 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -416,7 +416,7 @@
 }
 
 gprs_rlcmac_ul_tbf *tbf_alloc_ul(struct gprs_rlcmac_bts *bts, GprsMs *ms, int8_t use_trx,
-				 uint32_t tlli, uint8_t ta)
+				 uint32_t tlli)
 {
 	struct gprs_rlcmac_ul_tbf *tbf;
 
@@ -435,8 +435,6 @@
 	tbf->update_ms(tlli, GPRS_RLCMAC_UL_TBF);
 	OSMO_ASSERT(tbf->ms());
 
-	tbf->ms()->set_ta(ta);
-
 	return tbf;
 }