gdrom,viocd: Convert to bdops->check_events()

gdrom,viocd: Convert to bdops->check_events()

BugLink: http://bugs.launchpad.net/bugs/793702

commit 1c27030bd21e7e2c68ef5be9f28c63778cf4b27f upstream.

Convert gdrom and viocd from ->media_changed() to ->check_events().

It's unclear how the conditions are cleared and it's possible that it
may generate spurious events when polled.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>