backlight: lcd: Do not include <linux/fb.h> in lcd header

With the exception of fb_notifier_callback(), none of the lcd code
uses fbdev; especially not the lcd drivers. Remove the include
statement for <linux/fb.h> from the public lcd header.

v2:
- fix typos in commit description

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240906075439.98476-29-tzimmermann@suse.de


Signed-off-by: Lee Jones <lee@kernel.org>