Windows: Update ValidDataLength on all nonPagingIo

Windows: Update ValidDataLength on all nonPagingIo

Instead of updating the Fcb->Header.ValidDataLength only when
processing cached writes, update it for all non-PagingIo extending writes.
This ensures that a file that is extended by a mixture of cached and
non-cached (NO_INTERMEDIATE_BUFFERING) writes will properly trigger a
page fault when the Windows cache manager does not have a complete page
cached.

Change-Id: I255bb667e33fadd07eb8961901d33707812a8406
Reviewed-on: http://gerrit.openafs.org/9742
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Peter Scott <pscott@kerneldrivers.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>