[e1] Enable dumping of LAPD frames again

Kill mi_set_pcap_fd from the header, introduce e1_set_pcap_fd
and call it from bsc_hack.c. Hook into abis_rsl_sendmsg and
_abis_nm_sendmsg for sending and e1inp_rx_ts for reading. It compiles
and should not cause a regression.
4 files changed