block: cleanup queue_wc_store

block: cleanup queue_wc_store

[ Upstream commit c4e21bcd0f9d01f9c5d6c52007f5541871a5b1de ]

Get rid of the local queue_wc_store variable and handling setting and
clearing the QUEUE_FLAG_WC flag diretly instead the if / else if.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230707094239.107968-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: 43c9835b144c ("block: don't allow enabling a cache on devices that don't support it")
Signed-off-by: Sasha Levin <sashal@kernel.org>