NR fix downlink IP

See merge request oai/openairinterface5g!806

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

See merge request oai/openairinterface5g!804

Develop Integration Branch : 2020 week 15

The following Merge Requests have been included :

* MR 789 : fix sync source configuration for eNB and B200-mini
* MR 795 : dft/fft in shared lib
* MR 795 : NR gNB SCF indication
* MR 798 : Improvements on the "default" LTE-4G scheduler

Merge remote-tracking branch 'origin/NR_RRCConfiguration_sync_source' into develop_integration_2020_w15_bis

Instead of looping over UEs and all DL config Req/HI DCI0, loop first
over all DL config Req/HI DCI0, and for each, match UE.  Lowers CPU
traffic for high traffic situations.

pucch receiver for format 0 reworked without floating point and no generation of sequences for each decoding attempt, SR detection integrated