FROMGIT: block: Add bio_max_segs

It's often inconvenient to use BIO_MAX_PAGES due to min() requiring the
sign to be the same.  Introduce bio_max_segs() and change BIO_MAX_PAGES to
be unsigned to make it easier for the users.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

BUG=b:273658215
TEST=`tast run $DUT arc.Boot.vm`
TEST=`tast run $DUT arc.Playstore.vm`

(cherry picked from commit 610664e2
 https://android.googlesource.com/kernel/common

 android13-5.10)

Change-Id: I0d70e3b46b9f97dc4db8b67a4138d6613e07d5f9
Signed-off-by: Ryuichiro Chiba <chibar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/4444989


Reviewed-by: Suleiman Souhlal <suleiman@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>