ar71xx: WNR2200: remove redundant GPIO for WLAN LED

ar71xx: WNR2200: remove redundant GPIO for WLAN LED

Without this patch, an extra entry appears for AR9287 GPIO
that duplicates WLAN LED but in fact drives nothing:

gpiochip1: GPIOs 502-511, ath9k-phy0:
 gpio-502 (                    |netgear:blue:wlan   ) out hi
 gpio-503 (                    |netgear:amber:test  ) out hi
 gpio-504 (                    |netgear:green:power ) out lo
 gpio-505 (                    |rfkill              ) in  hi
 gpio-507 (                    |wps                 ) in  hi
 gpio-508 (                    |reset               ) in  hi
 gpio-510 (                    |ath9k-phy0          ) out hi <===!

The pin pointed above is default LED GPIO (8) for AR9287.
For WNR2200 it is not connected anywhere - pin 0 drives blue WLAN
LED instead - but initialization code is missing that information.

This fix calls ap9x_pci_setup_wmac_led_pin() function at device
setup, forcing WLAN LED pin to be 0 and removing redundant entry.

Signed-off-by: Michal Cieslakiewicz <michal.cieslakiewicz@wp.pl>