drm/qxl: Handle all errors in qxl_surface_evict

Only EBUSY error was handled. This could cause code to believe
reserve was successful while it failed.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>