The allocation for vfpriv is being leaked on an error return path,
fix this by kfree'ing it before returning.
Detected by CoverityScan, CID#1475380 ("Resource Leak")
Fixes: 6a37c49a94 ("drm/virtio: Handle context ID allocation errors")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20181107203122.6861-1-colin.king@canonical.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>