ath9k: fix ath9k_hw_apply_gpio_override so that it's effective

ath9k: fix ath9k_hw_apply_gpio_override so that it's effective

I discovered another bug in the ath9k WNDR3700 quirk fix from r23822.
ath9k_hw_apply_gpio_override was testing the original value of gpio_mask
to determine which bits were appropriate, instead of testing the shifted
value. Because bit 0 is always clear in the original value, this
resulted in no calls to set the GPIOs, an improperly-configured radio,
and reduced RSSI on other systems listening to the radio.

Signed-off-by: Mark Mentovai <mark@moxienet.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@23890 3c298f89-4303-0410-b956-a3cf2f4a3e73