gmm: Update DRX params during rx RAU REQ

The DRX params where already parsed in GMM Attached Req and transmitted
to PCU over BSSGP DL UD packets, but it was not being updated if the MS
changed it during RAU Req.

TS 24.008 9.4.14.3 DRX parameter:
"This IE shall be included if the MS changes the access network
from GSM to UMTS, or the MS wants to indicate new DRX parameters
to the network."

Change-Id: I1dd7f8f161280dd017c337eacc3aa2be4ccd65ea
---
M src/sgsn/gprs_gmm.c
1 file changed, 22 insertions(+), 0 deletions(-)

diff --git a/src/sgsn/gprs_gmm.c b/src/sgsn/gprs_gmm.c
index 547edbb..3cc3055 100644
--- a/src/sgsn/gprs_gmm.c
+++ b/src/sgsn/gprs_gmm.c
@@ -1766,6 +1766,10 @@
 		/* Update the MM context with the new (i.e. foreign) TLLI */
 		mmctx->gb.tlli = msgb_tlli(msg);
 	}
+	/* Update the MM context with the new DRX params */
+	if (TLVP_PRESENT(&tp, GSM48_IE_GMM_DRX_PARAM))
+		memcpy(&mmctx->drx_parms, TLVP_VAL(&tp, GSM48_IE_GMM_DRX_PARAM), sizeof(mmctx->drx_parms));
+
 	/* FIXME: Update the MM context with the MS radio acc capabilities */
 	/* FIXME: Update the MM context with the MS network capabilities */
 

