gpio: Fix a documentation spelling mistake

Simple etraneous letter.

Reported-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2018-01-21 16:52:31 +01:00
commit 2046362cf1