drm/virtio: Unlock reservations on dma_resv_reserve_fences() error

Unlock reservations on dma_resv_reserve_fences() error to fix recursive
locking of the reservations when this error happens.

Cc: stable@vger.kernel.org
Fixes: c8d4c18b ("dma-buf/drivers: make reserving a shared slot mandatory v4")
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220630200726.1884320-5-dmitry.osipenko@collabora.com


Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>