MIPS: lantiq: Fix attributes of of_device_id structure

According to the checkpatch the driver structure of_device_id requires
to be const and with attribute __initconst. Change it accordingly.
Signed-off-by: Petr Cvek <petrcvekcz@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: hauke@hauke-m.de
Cc: john@phrozen.org
Cc: linux-mips@vger.kernel.org
Cc: openwrt-devel@lists.openwrt.org
Cc: pakahmar@hotmail.com

arch/mips/lantiq/irq.c

@@ -347,7 +347,7 @@ unsigned int get_c0_compare_int(void)
 	return CP0_LEGACY_COMPARE_IRQ;
 }
 
-static struct of_device_id __initdata of_irq_ids[] = {
+static const struct of_device_id of_irq_ids[] __initconst = {
 	{ .compatible = "lantiq,icu", .data = icu_of_init },
 	{},
 };