04.08: log protocol discriminators and message types by name

On incoming 04.08 messages, we log only the protocol discriminator in
decimal. Enhance: log pdisc and message type in hex, and also log the
protocol and message type as human readable string.

Also adjust the msc_vlr tests' log statements for wrapped rx/tx functions
of dtap from/to the MS.

Adjust the expected output of msc_vlr_tests.

Change-Id: Ida205d217e304337d816b14fd15e2ee435e7397d
Depends: libosmocore change-id I0fca8e95ed5c2148b1a7440eff3fc9c7583898df
11 files changed