libwmc: remove it
The WMC protocol was only present on older Panasonic/Verizon devices from the 2006 - 2011 timeframe. The last device to support WMC was the UML290 which also supported QMI (which is much more functional). ModemManager also never used WMC support and it was never significantly reverse engineered.
So remove WMC code from git; it'll still be in the history if anyone cares in the future.