drm/qxl: qxl_release leak in qxl_draw_dirty_fb()

drm/qxl: qxl_release leak in qxl_draw_dirty_fb()

BugLink: https://bugs.launchpad.net/bugs/1878256
commit 85e9b88af1e6164f19ec71381efd5e2bcfc17620 upstream.

ret should be changed to release allocated struct qxl_release

Cc: stable@vger.kernel.org
Fixes: 8002db6336dd ("qxl: convert qxl driver to proper use for reservations")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Link: http://patchwork.freedesktop.org/patch/msgid/22cfd55f-07c8-95d0-a2f7-191b7153c3d4@virtuozzo.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>