tracing: always define trace_{irq,preempt}_{enable_disable}

We get a build error in the irqsoff tracer in some configurations:

kernel/trace/trace_irqsoff.c: In function 'trace_preempt_on':
kernel/trace/trace_irqsoff.c:855:2: error: implicit declaration of function 'trace_preempt_enable_rcuidle'; did you mean 'trace_irq_enable_rcuidle'? [-Werror=implicit-function-declaration]
  trace_preempt_enable_rcuidle(a0, a1);

The problem is that trace_preempt_enable_rcuidle() has different
definition based on multiple Kconfig symbols, but not all combinations
have a valid definition.

This changes the conditions so that we always get exactly one
definition of each of the four tracing macros. I have not tried
to verify that these definitions are sensible, but now we
can build all randconfig combinations again.

Link: http://lkml.kernel.org/r/20171019083230.2450779-1-arnd@arndb.de

Fixes: d5915816

 ("tracing: Add support for preempt and irq enable/disable events")
Acked-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>