Linux: 2.6.38: dentry->d_count is not an atomic

Linux: 2.6.38: dentry->d_count is not an atomic

d_count is now an int protected by the dentry's d_lock.
Take the lock when we use it, instead of using an atomic_*
function.

Reviewed-on: http://gerrit.openafs.org/3883
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry-picked from commit 281f5bf5fbb0a546edcce62ef4e097ae9bbdbf73)

Change-Id: I45caa6aef451a7f93bfa43dfb1ebe9b0b856fbd0
Reviewed-on: http://gerrit.openafs.org/3935
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>