ARM: ixp4xx: Convert to SPARSE_IRQ

This localizes the <mach/irqs.h> header to the mach-ixp4xx
directory, removes NR_IRQS and switches IXP4xx over to using
SPARSE_IRQ.

This is a prerequisite for DT support.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/mach-ixp4xx/fsg-pci.c

@@ -22,6 +22,8 @@
 #include <asm/mach/pci.h>
 #include <asm/mach-types.h>
 
+#include "irqs.h"
+
 #define MAX_DEV		3
 #define IRQ_LINES	3