UPSTREAM: block: disable entropy contributions for nonrot devices

(cherry picked from commit b277da0a8a594308e17881f4926879bd5fca2a2d)

Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.

Historically, all block devices have automatically made entropy
contributions.  But as previously stated in commit e2e1a148 ("block: add
sysfs knob for turning off disk entropy contributions"):
    - On SSD disks, the completion times aren't as random as they
      are for rotational drives. So it's questionable whether they
      should contribute to the random pool in the first place.
    - Calling add_disk_randomness() has a lot of overhead.

There are more reliable sources for randomness than non-rotational block
devices.  From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.

Change-Id: Id8d2dde2f2da384476be98ed064c1bb0c5df49cd
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Based on commit: https://github.com/deadman96385/android_kernel_nextbit_msm8992/commit/22d30d052d51d8adc16d86070e6e74202a52287c