Before this commit each time the message was captured, it entered the
default switch statement, which is meant to show that  we received an
uknown IEI.

Now after the DNN IEI, we set offset=msg_length, to exit the
switch.

Change input command line from -g 2 A l to -g A,l and add channel correlation level as command line option in ulsim

Implementation of tables G.2.1.1-2, G.2.1.1-3 and G.2.1.1-4 of TS 38.104, for TDLA30, TDLB100 and TDLC300 channel models