gpio: uapi: remove whitespace

Remove leading whitespace in ABI v1 comment.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20201005070329.21055-5-warthog618@gmail.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>