powerpc: Make "intspec" pointers in irq_host->xlate() const

Writing a driver using SCLPC on the MPC5200B I detected, that the
intspec arrays to map irqs to Linux virq cannot be const, because the
mapping and xlate functions only take non const pointers. All those
functions do not modify the intspec, so a const pointer could be used.

Signed-off-by: Roman Fietze <roman.fietze@telemotive.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
index ba8f1f7..0a55db8 100644
--- a/arch/powerpc/sysdev/i8259.c
+++ b/arch/powerpc/sysdev/i8259.c
@@ -198,7 +198,7 @@
 }
 
 static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
-			    u32 *intspec, unsigned int intsize,
+			    const u32 *intspec, unsigned int intsize,
 			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 {
 	static unsigned char map_isa_senses[4] = {