drm/bochs: Validate display modes against available video memory

For each mode, test the required memory against the available video
memory. Filters out modes that do not fit into display memory.

Also remove the old test against the 4 MiB limit. It is now obsolete
and did not necessarily produce correct results.

v2:
- fix __udivdi3 linker error (kernel test robot)
- fix vdisplay and hdisplay usage

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240902105546.792625-10-tzimmermann@suse.de