Reapply "ANDROID: block: Add support for filesystem requests and small segments"

This reverts commit I764adf995cae6b485d4d98e410c78128a88647e0.

Bug: 333812722
Bug: 308663717
Bug: 319125789
Change-Id: Ie7f03b9d1ab67a33ccbc4311ba26cd746e1aaa22
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[jyescas@google.com: Call blk_segments() in blk_mq_submit_bio()
                     for the case when request is defined or it
                     is null]
Signed-off-by: Juan Yescas <jyescas@google.com>