audit: use macros for unset inode and device values

Clean up a number of places were casted magic numbers are used to represent
unset inode and device numbers in preparation for the audit by executable path
patch set.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: enclosed the _UNSET macros in parentheses for ./scripts/checkpatch]
Signed-off-by: Paul Moore <pmoore@redhat.com>

diff --cc include/linux/audit.h
Simple merge

diff --cc kernel/audit.c
Simple merge

diff --cc kernel/audit_watch.c
Simple merge

diff --cc kernel/auditsc.c
Simple merge