Convert avc_audit in security/selinux/avc.c to use lsm_audit.h,
for better maintainability and for less code duplication.

 - changed selinux to use common_audit_data instead of
   avc_audit_data
 - eliminated code in avc.c and used code from lsm_audit.h instead.

I have tested to make sure that the avcs look the same before and
after this patch.
Signed-off-by: NThomas Liu <tliu@redhat.com>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NJames Morris <jmorris@namei.org>