video: constify fb ops across all drivers

Now that the fbops member of struct fb_info is const, we can start
making the ops const as well.

This does not cover all drivers; some actually modify the fbops struct,
for example to adjust for different configurations, and others do more
involved things that I'd rather not touch in practically obsolete
drivers. Mostly this is the low hanging fruit where we can add "const"
and be done with it.

v3:
- un-constify atyfb, mb862xx, nvidia and uvesabf (0day)

v2:
- fix typo (Christophe de Dinechin)
- use "static const" instead of "const static" in mx3fb.c
- also constify smscufx.c

Cc: linux-fbdev@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ce67f14435f3af498f2e8bf35ce4be11f7504132.1575390740.git.jani.nikula@intel.com

drivers/video/fbdev/s3fb.c

@@ -1037,7 +1037,7 @@ static int s3fb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
 
 /* Frame buffer operations */
 
-static struct fb_ops s3fb_ops = {
+static const struct fb_ops s3fb_ops = {
 	.owner		= THIS_MODULE,
 	.fb_open	= s3fb_open,
 	.fb_release	= s3fb_release,