s390: Use generic TIF bits

No point in defining generic items and the upcoming RSEQ optimizations are
only available with this _and_ the generic entry infrastructure, which is
already used by s390. So no further action required here.

This leaves a comment about the AUDIT/TRACE/SECCOMP bits which are handled
by SYSCALL_WORK in the generic code, so they seem redundant, but that's a
problem for the s390 wizards to think about.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com>