gpio: Fix gpio direction flags not getting set

GPIO direction flags are not getting set because
an 'if' statement is the wrong way around.

Cc: Stable <stable@vger.kernel.org> # 3.15+
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>