trxcon/l1sched: fix UL FACCH regression in tx_tchh_fn()

In ad8f7794 I introduced a regression by removing the line setting
lchan->ul_facch_blocks, breaking transmission of Uplink FACCH/H.

Change-Id: I4f2bbbd30c7d5dbb979b54455561df3c0cc12aac
Fixes: ad8f7794 "trxcon/l1sched: remove redundant TCH/[FH] prim length checks"
---
M src/host/trxcon/src/sched_lchan_tchh.c
1 file changed, 16 insertions(+), 0 deletions(-)

diff --git a/src/host/trxcon/src/sched_lchan_tchh.c b/src/host/trxcon/src/sched_lchan_tchh.c
index acf362e..3832deb 100644
--- a/src/host/trxcon/src/sched_lchan_tchh.c
+++ b/src/host/trxcon/src/sched_lchan_tchh.c
@@ -456,6 +456,9 @@
 		goto send_burst;
 	}
 
+	if (msgb_l2len(lchan->prim) == GSM_MACBLOCK_LEN)
+		lchan->ul_facch_blocks = 6;
+
 	/* populate the buffer with bursts */
 	switch (lchan->tch_mode) {
 	case GSM48_CMODE_SIGN:

