drm/sysfb: Share helpers for integer validation

Provide sysfb helpers for validating framebuffer integer values
against limits. Update drivers. If a driver did not specify a limit
for a certain value, use INT_MAX.

v2:
- declare module information near EOF (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250410083834.10810-3-tzimmermann@suse.de