gsm_rlcmac.cpp: fix global-buffer-overflow error reported by ASAN

Port from wireshark.git f751918476bdde65f2289b86245a3c30dace6730.

Ported-by: Pau Espin Pedrol <pespin@sysmocom.de>
Change-Id: I70d4ff3e137b5fd13d367bd4ea6ab501e81e7a87
diff --git a/src/gsm_rlcmac.cpp b/src/gsm_rlcmac.cpp
index 839bfbb..403b65e 100644
--- a/src/gsm_rlcmac.cpp
+++ b/src/gsm_rlcmac.cpp
@@ -1105,7 +1105,10 @@
   M_NEXT_EXIST (IU_Mode_Channel_Request_Desk_t, Exist_RLC_BLOCK_COUNT, 1),
   M_UINT       (IU_Mode_Channel_Request_Desk_t,  RLC_BLOCK_COUNT,  8),
 
-  M_NEXT_EXIST (IU_Mode_Channel_Request_Desk_t, Exist_Iu_Mode_ChRequestDesk, 1), /* Don't use M_REC_TARRAY as we don't support multiple TBFs */
+  /* Don't use M_REC_TARRAY as we don't support multiple TBFs
+  M_NEXT_EXIST (IU_Mode_Channel_Request_Desk_t, Exist_Iu_Mode_ChRequestDesk, 1),
+  M_TYPE       (IU_Mode_Channel_Request_Desk1, IU_Mode_Channel_Request_Desk_t),*/
+  M_UINT       (IU_Mode_Channel_Request_Desk_t, Exist_Iu_Mode_ChRequestDesk, 1),
 
 CSN_DESCR_END  (IU_Mode_Channel_Request_Desk_t)