fbdev: Use /* */ comment in initializer macro

Use /* */ in initializer macro to avoid out-commenting the comma
at the end of the line.

Reported-by: Christian König <ckoenig.leichtzumerken@gmail.com>
Closes: https://lore.kernel.org/dri-devel/20230530150253.22758-1-tzimmermann@suse.de/T/#m356cda2679c17d7a01f30ce2b5282cd9046ea6d4


Fixes: f1061fa6 ("fbdev: Add initializer macros for struct fb_ops")
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230614131253.10208-1-tzimmermann@suse.de