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/tsi108_pci.c b/arch/powerpc/sysdev/tsi108_pci.c
index cf244a4..02f6009 100644
--- a/arch/powerpc/sysdev/tsi108_pci.c
+++ b/arch/powerpc/sysdev/tsi108_pci.c
@@ -398,7 +398,7 @@
 	DBG("%s(%d, 0x%lx)\n", __func__, virq, hw);
 	if ((virq >= 1) && (virq <= 4)){
 		irq = virq + IRQ_PCI_INTAD_BASE - 1;
-		get_irq_desc(irq)->status |= IRQ_LEVEL;
+		irq_to_desc(irq)->status |= IRQ_LEVEL;
 		set_irq_chip(irq, &tsi108_pci_irq);
 	}
 	return 0;