drm: qxl: Fix error handling at qxl_device_init

If qxl_device_init fails on creating resources and does not report it,
then qxl module will catch null pointer exception on remove, or on
probe's error path.

The patch adds error path with resources release into qxl_device_init.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Link: http://patchwork.freedesktop.org/patch/msgid/20180727115440.11112-1-vasilyev@ispras.ru


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