rtp2trau_hr16: set CRC bits correctly

The code previously failed to set the CRC bits in the TRAU frame
output, containing a misleading comment that this operation is done
by the TRAU frame encoding function (it isn't).  Set these bits
correctly in the rtp2trau step, like we do for EFR.

Change-Id: I5c8aa5891e3862f978f14093bff46bd00b6702a5
---
M src/trau/trau_rtp_conv.c
1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/trau/trau_rtp_conv.c b/src/trau/trau_rtp_conv.c
index 21322fc..b8f554c 100644
--- a/src/trau/trau_rtp_conv.c
+++ b/src/trau/trau_rtp_conv.c
@@ -47,7 +47,7 @@
 
 
 /*
- * EFR TRAU parity
+ * EFR TRAU parity (also used for HR)
  *
  * g(x) = x^3 + x^1 + 1
  */
@@ -461,11 +461,12 @@
 		tf->ufi = 0;
 	else
 		tf->ufi = 1;
-	/* CRC is computed by TRAU frame encoder */
 	if (data_len)
 		osmo_pbit2ubit(tf->d_bits, data, GSM_HR_BYTES * 8);
 	else
 		memset(tf->d_bits, 0, GSM_HR_BYTES * 8);
+	/* CRC is *not* computed by TRAU frame encoder - we have to do it */
+	osmo_crc8gen_set_bits(&gsm0860_efr_crc3, tf->d_bits, 44, tf->crc_bits);
 
 	return 0;
 }

