drm/vmwgfx: Refactor resource manager's hashtable to use linux/hashtable implementation.

Vmwgfx's hashtab implementation needs to be replaced with linux/hashtable
to reduce maintenance burden.
Refactor cmdbuf resource manager to use linux/hashtable.h implementation
as part of this effort.

Signed-off-by: Maaz Mombasawala <mombasawalam@vmware.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221022040236.616490-4-zack@kde.org