keyboard: cancel keybind_repeat on reconfigure

keyboard: cancel keybind_repeat on reconfigure

Currently we may end up in an endless loop of Reconfigure requests
if the Reconfigure action was called by a keybind. If the reconfigure
takes too long (which may happen on slow systems with libsfdo full
debug logging for example) the reconfigure might be triggered again
and again.

To prevent that, simply cancel all keybind_repeat timers on reconfigure.