Remove the bdev_type and sysfs_block_type SELinux attributes

Remove these SELinux attributes since adding these attributes introduces
a depencency from vendor SELinux policies on the generic SELinux policy,
something that is not allowed. This patch includes a revert of commit
8b2b951349c4 ("Restore permission for shell to list /sys/class/block").
That commit is no longer necessary since it was a bug fix for the
introduction of the sysfs_block type.

Bug: 202520796
Test: source build/envsetup.sh && lunch aosp_x86_64 && m && launch_cvd
Change-Id: Ic6ae835768212648ca09fd5c83c39180103c3b1b
Signed-off-by: Bart Van Assche <bvanassche@google.com>
7 files changed