drm/virtio: Use UUID API for importing the UUID

There is import_uuid() function which imports u8 array to the uuid_t.
Use it instead of open coding variant.

This allows to hide the uuid_t internals.

Reviewed-by: David Stevens <stevensd@chromium.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20201013132714.70973-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>