Fix access to video_is_primary_device() when compiled without CONFIG_VIDEO

When compiled without CONFIG_VIDEO the architecture specific
implementations of video_is_primary_device() include prototypes and
assume that video-common.c will be linked. Guard against this so that the
fallback inline implementation that returns false will be used when
compiled without CONFIG_VIDEO.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506221312.49Fy1aNA-lkp@intel.com/
Link: https://lore.kernel.org/r/20250811162606.587759-2-superm1@kernel.org


Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>