Revert "vfs: make AIO use the proper rw_verify_area() area helpers"

This change is already present in current kernel 3.10 via commit
a70b52ec.

This reverts commit 99315b97.

Change-Id: I514162e7cd0a6dfd05c16c246b7954537f0af109
Tracked-On: https://jira01.devtools.intel.com/browse/AW-2060


Signed-off-by: Victor Tasayco Loarte <victorx.tasayco.loarte@intel.com>