Revert "[mce] Better LED pattern management"

This reverts commit 670cd55e9a179684674035fd6345842974e0b9c1.

The logic here proved to be inadequate in further testing, we cannot
catch all display on scenarios reliably since there is not enough
information available through the MCE signals.

To make this work properly, MCE needs to learn new tricks.
[mce] Let MCE clear patterns since it knows better when to do that

MCE can monitor user activity with more granularity than what we have
available in ngfd, so it's better to let it decide when the LED pattern
should be cleared.

Old functionality is available through 'mce.clear_pattern = true' property.

Signed-off-by: Kalle Vahlman <kalle.vahlman@movial.com>
Merge pull request #34 from kvahlman/mce-handles-leds

Mce handles leds