ARM: omap2: Rewrite WLAN quirk to use GPIO descriptors

The OMAP2 platform data quirk is using the global GPIO numberspace
to obtain two WLAN GPIOs to drive power and xcvr reset GPIO
lines during start-up.

Rewrite the quirk to use a GPIO descriptor table so we avoid using
global GPIO numbers.

This gets rid of the final dependency on the legacy <linux/gpio.h>
header from the OMAP2/3 platforms.

Fixes: 92bf78b3 ("gpio: omap: use dynamic allocation of base")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>