m68knommu: add read_barrier_depends() and irqs_disabled_flags()

/home/bigeasy/git/linux-2.6-ftrace/kernel/trace/trace.c: In function 'tracing_generic_entry_update':
/home/bigeasy/git/linux-2.6-ftrace/kernel/trace/trace.c:802: error: implicit declaration of function 'irqs_disabled_flags'
make[3]: *** [kernel/trace/trace.o] Error 1
/home/bigeasy/git/linux-2.6-ftrace/kernel/trace/ftrace.c: In function 'ftrace_list_func':
/home/bigeasy/git/linux-2.6-ftrace/kernel/trace/ftrace.c:61: error: implicit declaration of function 'read_barrier_depends'

Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>