powerpc: Remove get_irq_desc()

get_irq_desc() is a powerpc-specific version of irq_to_desc(). That
is reason enough to remove it, but it also doesn't know about sparse
irq_desc support which irq_to_desc() does (when we enable it).

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/xilinx_intc.c b/arch/powerpc/sysdev/xilinx_intc.c
index 40edad52..ab74371 100644
--- a/arch/powerpc/sysdev/xilinx_intc.c
+++ b/arch/powerpc/sysdev/xilinx_intc.c
@@ -79,7 +79,7 @@
 
 static int xilinx_intc_set_type(unsigned int virq, unsigned int flow_type)
 {
-	struct irq_desc *desc = get_irq_desc(virq);
+	struct irq_desc *desc = irq_to_desc(virq);
 
 	desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
 	desc->status |= flow_type & IRQ_TYPE_SENSE_MASK;