The xlate() function returns 0 or a negative error code. Returning the
error code blindly will be seen as an huge irq number by the calling
function because irq_create_of_mapping() returns an unsigned value.

Return 0 (NO_IRQ) as required.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>