Linux: Fix misleading indentation and other whitespace

Linux: Fix misleading indentation and other whitespace

Commit 7edc6694e7632c9736bd1516935604a638165313 introduced a
misleading indentation of a line in afs_linux_prefetch. Correct
it, and once here remove trailing whitespace throughout the file.

Reviewed-on: https://gerrit.openafs.org/12253
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 3609ebcfa3f70ca7612364c0cc2345b1d7f1096b)

Change-Id: I0d42c6751b835308c692c0ebb7d217f56ad5cf2a
Reviewed-on: https://gerrit.openafs.org/12254
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>