drm/vmwgfx: Remove reference to struct drm_device.pdev

Using struct drm_device.pdev is deprecated in favor of drm_device.dev.
The reference to the field was reintroduced during a rebase.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 9703bb32 ("drm/vmwgfx: Switch to a managed drm device")
Reviewed-by: Zack Rusin <zackr@vmware.com>
Cc: Zack Rusin <zackr@vmware.com>
Cc: Martin Krastev <krastevm@vmware.com>
Cc: Roland Scheidegger <sroland@vmware.com>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: dri-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210118131420.15874-6-tzimmermann@suse.de