drop MGCP client from osmo-bsc

After osmo-mgw change I8e0b2d2a399b77086a36606f5e427271c6242df1, there now is a
separated libosmo-mgcp-client, and osmo-bsc needs adjusting.

But besides having an unused struct in gsm_network, osmo-bsc does not yet use
its MGCP client; these are merely plans for the future. Until we do, let's just
drop the dependency entirely.

Change-Id: I6402c7cbe58dacae7630f7f03819f8102e54c699
1 file changed