Revert "igc: Export LEDs"

This reverts commit cf833182.

There are better Linux interfaces to export the different LED modes
and blinking reasons.

Revert this patch for now and come up with better solution later.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20210719101640.16047-1-kurt@linutronix.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>