msc: add as_mgcp_ack_all_dlcx

Will be used by MSC_Tests.TC_call_re_establishment in
Ifdff5573eeb3b3d41e8599b9b0228411d2576864

Related: SYS#5130
Change-Id: Ic63fa41fa2e5d392d39f6b5f9edd3952aa6a9ee9
1 file changed