gpio: driver.h: fix kernel-doc markup

There is one parameter with a wrong name at kernel-doc macro:

./include/linux/gpio/driver.h:499: warning: Function parameter or member 'gc' not described in 'gpiochip_add_data'
./include/linux/gpio/driver.h:499: warning: Excess function parameter 'chip' description in 'gpiochip_add_data'

Fix it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>