audit: fix coding style issues

Fix various coding style issues across the audit subsystem flagged
by checkpatch.pl script to adhere to kernel coding standards.

Specific changes include:
- kernel/auditfilter.c: Move the open brace '{' to the previous line
  for the audit_ops array declaration.
- lib/audit.c: Add a required space before the open parenthesis '('.
- include/uapi/linux/audit.h: Enclose the complex macro value for
  AUDIT_UID_UNSET in parentheses.

Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>