cdrom: don't attempt to fiddle with cdo->capability

cdrom: don't attempt to fiddle with cdo->capability

[ Upstream commit 8f94004e2a51a3ea195cf3447eb5d5906f36d8b3 ]

We can't modify cdo->capability as it is defined as a const.
Change the modification hack to just WARN_ON_ONCE() if we hit
any of the invalid combinations.

This fixes a regression for pcd, which doesn't work after the
constify patch.

Fixes: 853fe1bf7554 ("cdrom: Make device operations read-only")
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>