gpio: Fix checkpatch.pl issues

This patch fixes some issues given by checkpatch. Fixes include
bracket placement, spacing and indenting.

Signed-off-by: Daniel Lockyer <thisisdaniellockyer@gmail.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>