auxdisplay: constify fb ops

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

Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Cc: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/31c18e3ce9d6962aabda4799b3051039ff591c92.1575390741.git.jani.nikula@intel.com

drivers/auxdisplay/cfag12864bfb.c

@@ -57,7 +57,7 @@ static int cfag12864bfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	return vm_map_pages_zero(vma, &pages, 1);
 }
 
-static struct fb_ops cfag12864bfb_ops = {
+static const struct fb_ops cfag12864bfb_ops = {
 	.owner = THIS_MODULE,
 	.fb_read = fb_sys_read,
 	.fb_write = fb_sys_write,

drivers/auxdisplay/ht16k33.c

@@ -228,7 +228,7 @@ static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	return vm_map_pages_zero(vma, &pages, 1);
 }
 
-static struct fb_ops ht16k33_fb_ops = {
+static const struct fb_ops ht16k33_fb_ops = {
 	.owner = THIS_MODULE,
 	.fb_read = fb_sys_read,
 	.fb_write = fb_sys_write,