usrp_lib: setting master clock rate to 30.72 and filter to 20MHz for all cases to improve noise figure and channel response

UHD interfacing (master clock 30.72, bandwidths on 5/10/20 @ 20 MHz), RX gain calibration back to normal.

Merge branch 'bugfix-48-L1L2signaling' of https://gitlab.eurecom.fr/oai/openairinterface5g into bugfix-48-L1L2signaling

Merge branch 'bugfix-48-L1L2signaling' of https://gitlab.eurecom.fr/oai/openairinterface5g into bugfix-48-L1L2signaling

Conflicts:
	openair1/SCHED/phy_procedures_lte_eNb.c

bugfixing for UL. Remaining problems: CCE allocations in subframe 5 lead to occasional illegal DCI allocations (affects UL DCI which is missed by UE). waveform compliance with CQI in ULSCH.

added a new check for illegal file permissions to mbmssim.c, to avoid a segfault if permissions are invalid.