ramips: fix Youku-YK1 support

ramips: fix Youku-YK1 support

Remove the ephy-pins from the ethernet device tree node. The ephy-pins
are useed to controll the ePHY LEDs and this board doesn't have these.
Instead one of the ePHY pins is used in GPIO mode to control the WAN
LED.

Use the switch LED trigger to control the WAN LED. Move the power LED
handling to diag.sh to show the boot status via this LED.

Add the missing kernel packages for USB and microSD card reader to the
default package selection.

Fix the maximum image size value. The board has a 32MByte flash chip.

Fixes: FS#1055
Signed-off-by: Edmunt Pienkowsky <roed@onet.eu>
[make the commit message more verbose, remove GPIO pinmux for pins not
used as GPIOs]
Signed-off-by: Mathias Kresin <dev@kresin.me>