UE/EMM: move _emm_data to nas_user_t

openair3/NAS/UE/EMM/Attach.c

openair3/NAS/UE/EMM/Authentication.c

openair3/NAS/UE/EMM/Detach.c

openair3/NAS/UE/EMM/EmmStatusHdl.c

openair3/NAS/UE/EMM/Identification.c

openair3/NAS/UE/EMM/IdleMode.c

openair3/NAS/UE/EMM/IdleMode.h

openair3/NAS/UE/EMM/LowerLayer.c

openair3/NAS/UE/EMM/SAP/EmmDeregisteredNoCellAvailable.c

openair3/NAS/UE/EMM/SAP/EmmDeregisteredPlmnSearch.c

openair3/NAS/UE/EMM/SAP/EmmRegisteredInitiated.c

openair3/NAS/UE/EMM/SAP/emm_as.c

openair3/NAS/UE/EMM/SAP/emm_esm.c

openair3/NAS/UE/EMM/SecurityModeControl.c

openair3/NAS/UE/EMM/emmData.h

openair3/NAS/UE/EMM/emm_main.c

openair3/NAS/UE/EMM/emm_main.h

openair3/NAS/UE/EMM/emm_proc.h

openair3/NAS/UE/nas_proc.c

openair3/NAS/UE/nas_proc.h