powerpc/ibmebus: Get rid of the IRQ mapping in ibmebus_free_irq()

ibmebus_free_irq() frees the IRQ but does not remove its mapping which
results in stale entries in the map.

Fix this by adding a call to irq_dispose_mapping() in ibmebus_free_irq().

---
 arch/powerpc/kernel/ibmebus.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

index 64299d2..7c65377 100644
@@ -231,6 +231,7 @@ void ibmebus_free_irq(u32 ist, void *dev_id)
 	unsigned int irq = irq_find_mapping(NULL, ist);
 
 	free_irq(irq, dev_id);
+	irq_dispose_mapping(irq);
 }
 EXPORT_SYMBOL(ibmebus_free_irq);
 

1.6.0.1.308.gede4c