mwl8787: drop pointless ternary expression

Signed-off-by: Bob Copeland <me@bobcopeland.com>
mwl8787: add support for firmware monitor cmd

Just testing to get RX working, this adds code for the monitoring
feature, hardcoded to listen to channel 1.  Turns out stock firmware
doesn't support this, alas.

Signed-off-by: Bob Copeland <me@bobcopeland.com>