LU-7261 ldiskfs: clean up code style for large_xattr

LU-7261 ldiskfs: clean up code style for large_xattr

Clean up the code style for the large_xattr patches to match the
upstream kernel style (use ! instead of == 0, and similar), and
the original style of the code before the earlier versions of the
patch was applied.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Icffe339d1b002a55984856829afde9e3eae98bd9
Reviewed-on: http://review.whamcloud.com/16778
Tested-by: Jenkins
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>