audit: Fix some kernel-doc warnings

The current code provokes some kernel-doc warnings:
    security/lsm_audit.c:198: warning: Function parameter or member
      'ab' not described in 'dump_common_audit_data'

Signed-off-by: Bo Liu <liubo03@inspur.com>
[PM: description line wrap]
Signed-off-by: Paul Moore <paul@paul-moore.com>