jewel:ceph-disk:remove the special check to bcache devices

jewel:ceph-disk:remove the special check to bcache devices

if we skip partition when coming cross the bcache device in ceph-disk,
the udev can't detect the osd in such devices when we reboot the osd's host,
so the osd who deploy in bcache device can't auto start when the host restart.

And partition is now supported by bcache devices (https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/drivers/md/bcache?id=b8c0d911ac5285e6be8967713271a51bdc5a936a),
we can remove this special check now.

This cannot be cherry-picked from master because 'accept bcache devices as data disks' [21f0216](https://github.com/ceph/ceph/commit/21f0216287485e6cce8811f324fee804ef733524)
is a jewel-only feature not present in master.

Signed-off-by: Wei Qiaomiao <wei.qiaomiao@zte.com.cn>