LU-7465 llite: Do not track memory leak for kernel function

LU-7465 llite: Do not track memory leak for kernel function

Do not use OBD_FREE to track memory leak if memory
allocation is from kernel function iov_iter_get_pages_alloc().

Signed-off-by: Wally Wang <wang@cray.com>
Change-Id: If723123bffceb46e2a3b3738043e54c62b8c96cd
Reviewed-on: http://review.whamcloud.com/17342
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>