drm/vmwgfx: Stop hardcoding the PCI ID

Instead of hardcoding the VMware's PCI ID the code should be using the
public define for it. There's no functional change, it just makes
it obvious what we're dealing with.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211206172620.3139754-4-zack@kde.org