ARM: SIRF: make sirf irqchip driver optional since new SoCs will have GIC

New MARCO and POLO SoC use GIC, so make irq.c optional and enable it
only if we enable ARCH_PRIMA2 in Kconfig

Signed-off-by: Barry Song <Baohua.Song@csr.com>
diff --git a/arch/arm/mach-prima2/irq.c b/arch/arm/mach-prima2/irq.c
index a7b9415..7dee917 100644
--- a/arch/arm/mach-prima2/irq.c
+++ b/arch/arm/mach-prima2/irq.c
@@ -63,7 +63,7 @@
 
 	np = of_find_matching_node(NULL, intc_ids);
 	if (!np)
-		panic("unable to find compatible intc node in dtb\n");
+		return;
 
 	sirfsoc_intc_base = of_iomap(np, 0);
 	if (!sirfsoc_intc_base)