tracing: irqsoff: Fix compilation warning

When PROVE_LOCKING enabled, tracing_irq_cpu would be
unused variable, so move it under proper condition checks.

Change-Id: Ifb48dac8628a0084ed74930445fa95b35c661511
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
1 file changed