UPSTREAM: saner calling conventions for unlazy_child()

[ Upstream commit ae66db45 ]

same as for the previous commit - instead of 0/-ECHILD make
it return true/false, rename to try_to_unlazy_child().

Change-Id: Ie949437504bd8db7f22f78bfbe5d5141e9959cf8
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 36ec3120)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>