block/cgroup: Inline blkg_conf_{open,close}_bdev_frozen()

block/cgroup: Inline blkg_conf_{open,close}_bdev_frozen()

The blkg_conf_open_bdev_frozen() calling convention is not compatible
with lock context annotations. Fold both blkg_conf_open_bdev_frozen()
and blkg_conf_close_bdev_frozen() into their only caller. This patch
prepares for enabling lock context analysis.

The type of 'memflags' has been changed from unsigned long into unsigned
int to match the type of current->flags. See also <linux/sched.h>.

Reviewed-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://patch.msgid.link/05661d1555decc6dd5389174ba448d803b72ed9a.1780682325.git.bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>