leds: flash: remove stray include directive

Avoid including v4l2-controls.h, as this is stray code from the early
versions of the LED / V4L2 flash API integration patches. LED Flash
class doesn't depend on V4L2 subsystem.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>