ARM: mmp: remove NR_IRQS

Remove NR_IRQS and add a per machine .nr_irqs setting. Clean-up namespace
replacing usage of IRQ_BOARD_START with MMP_NR_IRQS.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
diff --git a/arch/arm/mach-mmp/gplugd.c b/arch/arm/mach-mmp/gplugd.c
index 8776546..f516e74 100644
--- a/arch/arm/mach-mmp/gplugd.c
+++ b/arch/arm/mach-mmp/gplugd.c
@@ -191,7 +191,7 @@
 
 MACHINE_START(GPLUGD, "PXA168-based GuruPlug Display (gplugD) Platform")
 	.map_io		= mmp_map_io,
-	.nr_irqs	= IRQ_BOARD_START,
+	.nr_irqs	= MMP_NR_IRQS,
 	.init_irq       = pxa168_init_irq,
 	.timer          = &pxa168_timer,
 	.init_machine   = gplugd_init,