LU-9558 llite: use struct vma_area_struct address field

LU-9558 llite: use struct vma_area_struct address field

The field virtual_address of struct vma_area_struct was
removed since it provided no better benefit than just
using the address field directly.

Linux-commit: 1a29d85eb0f19b7d8271923d8917d7b4f5540b3e

Change-Id: I05068cdf27c93c5b3201c76ec043bc6c0e66df1f
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/27281
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>