linux-phytec-ti

mips: pci-lantiq: Fix check for valid gpio

This patch fixes two checks for valid gpio number, formerly (wrongly)
considering zero as invalid, now using gpio_is_valid().

Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>