random: initialize the non-blocking pool via add_hwgenerator_randomness()

random: initialize the non-blocking pool via add_hwgenerator_randomness()

BugLink: http://bugs.launchpad.net/bugs/1615620
commit 3371f3da08cff4b75c1f2dce742d460539d6566d upstream.

If we have a hardware RNG and are using the in-kernel rngd, we should
use this to initialize the non-blocking pool so that getrandom(2)
doesn't block unnecessarily.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>