Address feedback from Dmitry:
 - input_sync() per event
 - maintain dev->keybit when remapping keys
 - since we handle remapping, keycodemax and keycodesize aren't used
 - on probe error, don't input_free_device() unless it registered

Also:
 - avoid reporting excess events
 - more bad-parameter paranoia in the remapping code

The excess event issue is basically that we don't have a way to
distinguish "button press" events from "button release" ones or
autorepeat events, so we should try being a bit smarter about
synthesizing them.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>