state: light indicator when either condition is satisfied

state: light indicator when either condition is satisfied

For the indicator to be set, it is sufficient for at least one of the
group, modifier, or control state to match; this is in line with the
xkblib spec, section 8.2 and ComputeAutoState() in xserver/xkb/xkbLEDs.c
(though the xserver implementation differs from the spec on some
points...).

This also adds a tiny optimization to skip the entire check if the mask
is empty.

Signed-off-by: Ran Benita <ran234@gmail.com>