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>

arch/powerpc/platforms/52xx/media5200.c

@@ -127,7 +127,7 @@ static int media5200_irq_map(struct irq_host *h, unsigned int virq,
 }
 
 static int media5200_irq_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)
 {