Windows: Interlocked operations for cm_buf

Windows: Interlocked operations for cm_buf

cm_buf flags and qFlags

Separate flags and qFlags in the cm_buf structure to improve
performance.

Reviewed-on: http://gerrit.openafs.org/5197
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
(cherry picked from commit 7ab34058120ebcc218e4061ea3ac3c8eeca6d83e)

Change-Id: I8cbc806833af630fb56c8ef388fe3a21df1f5478
Reviewed-on: http://gerrit.openafs.org/5218
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>