otherwise, if we only have a (negative) SR, the UE did not send
anything, and the PUCCH CQI is invalid

1: there can be 2bits AckNack + SR in PUCCH F0
2: when allocating csi_pucch, zero out struct
3: Make unfree resources a warning
4: When asserting, explain the issue

- Configure PUCCH Format 0 to be in separate RBs (each UE has dedicated
  resources)
- Configure RA preamble to be different per UE
- Configure CSI offset such that no two UEs have their report in the
  same frame

Nb_ue is not unique among UEs: consider 2 UEs present. The last UE has
CSI idx "2". Now the first UE disconnects, and a new UE connects. It
will also get CSI idx "2", and I assume this is not what we want.

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Integration Branch : 2021 week 14

See merge request oai/openairinterface5g!1121

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Mohammed Ismail <mohammed.ismail@openairinterface.org>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

The bug was:
connect a phone, disconnect, repeat five times. The fifth time the phone
does not reconnect because there is no free RA process.

When an UE is removed, we have to free associated RA processes.

MR !1111 : fix x2 without gnb  
-fix x2 without gnb (that is: the eNB is running without gNB, then we must not switch the UE to NR)
-exit gNB if eNB crashes (and exit eNB if gNB crashes)

MR !1102 : nr rlc: bugfix: fix NACK with range 
We do some sanity checks for incoming rlc control packets. One of them is to check that so_start is not > so_end when present.
But when 'range' is present and bigger than 1 it means that so_start refers to one PDU and so_end to another one. So we may well have so_start > so_end.
This MR fixes that and reorganizes a bit the code to do the check before processing and rejecting the PDU if the values are not correct. (Before this commit we were NACKing the whole PDUs if so_start > so_end.)
 
MR !1096 : build_oai: Add --sanitize-address option
-pass the -fsanitize=address option to the compiler which enables run-time checks for some kinds of memory mismanagement