dm vdo: remove all sysfs interfaces

Also update target major version number.

All info is (or will be) accessible through alternative interfaces
(e.g. "dmsetup message", module params, etc).

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: move indexer files into sub-directory

The goal is to assist high-level understanding of which code is
conceptually specific to VDO's indexer.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: fold thread-cond-var.c into thread-utils

Further cleanup is needed for thread-utils interfaces given many
functions should return void or be removed entirely because they
amount to obfuscation via wrappers.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: rename uds-threads.[ch] to thread-utils.[ch]

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: fix sparse warnings about missing statics

Addresses various sparse warnings like:
warning: symbol 'SYMBOL' was not declared. Should it be static?

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Susan LeGendre-McGhee <slegendr@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: use a proper Makefile for dm-vdo

Requires moving dm-vdo-target.c into drivers/md/dm-vdo/

This change adds a proper drivers/md/dm-vdo/Makefile and eliminates
the abnormal use of patsubst in drivers/md/Makefile -- which was the
cause of at least one build failure that was reported by the upstream
build bot.

Also, split out VDO's drivers/md/dm-vdo/Kconfig and include it from
drivers/md/Kconfig

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>