arm: Tell irq work about self IPI support

arm: Tell irq work about self IPI support

ARM irq work IPI support depends on SMP support. That information is
partly known at early boottime. Lets implement
arch_irq_work_has_interrupt() accordingly.

Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>