drm/vmwgfx: Port the framebuffer code to drm fb helpers

drm/vmwgfx: Port the framebuffer code to drm fb helpers

Instead of using vmwgfx specific framebuffer implementation use the drm
fb helpers. There's no change in functionality, the only difference
is a reduction in the amount of code inside the vmwgfx module.

drm fb helpers do not deal correctly with changes in crtc preferred mode
at runtime, but the old fb code wasn't dealing with it either.
Same situation applies to high-res fb consoles - the old code was
limited to 1176x885 because it was checking for legacy/deprecated
memory limites, the drm fb helpers are limited to the initial resolution
set on fb due to first problem (drm fb helpers being unable to handle
hotplug crtc preferred mode changes).

This also removes the kernel config for disabling fb support which hasn't
been used or supported in a very long time.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Maaz Mombasawala <mombasawalam@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20221022040236.616490-14-zack@kde.org