ramips: fix GB-PC1 and GB-PC2 LEDs

Add the missing LEDs for GB-PC2. Some of these LEDs don't exist on the
device schematics. Tests on a GB-PC2 by me and Petr proved otherwise.

Remove ethblack-green and ethblue-green LEDs for GB-PC1. They are not wired
to GPIO 3 or 4 and the wiring is currently unknown.

Set ethyellow-orange to display link state and activity of the ethyellow
interface for GB-PC2.

Link: https://github.com/ngiger/GnuBee_Docs/blob/master/GB-PCx/Documents/GB-PC2_V1.1_schematic.pdf
Tested-by: Petr Louda <petr.louda@outlook.cz>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>