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/chipsfb.c

@@ -79,7 +79,7 @@ static int chipsfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 			     u_int transp, struct fb_info *info);
 static int chipsfb_blank(int blank, struct fb_info *info);
 
-static struct fb_ops chipsfb_ops = {
+static const struct fb_ops chipsfb_ops = {
 	.owner		= THIS_MODULE,
 	.fb_check_var	= chipsfb_check_var,
 	.fb_set_par	= chipsfb_set_par,