ideapad: read brightness setting on brightness key notify

ideapad: read brightness setting on brightness key notify

commit 2165136585b5c7d6f118f1d90fbde550bb7de212 upstream.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=25922
On ideapad Y530, the brightness key notify will be blocked if the last notify
is not responsed by getting the brightness value. Read value when we get the
notify shall fix the problem and will not have any difference on other ideapads.

Signed-off-by: Ike Panhc <ike.pan@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>