arm: omap: irq: add a global omap_nr_irqs variable

this will cache number of irqs. Also in preparation
for removal of irq_banks array.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/irq.c

@@ -70,6 +70,7 @@ static struct omap_irq_bank {
 
 static struct irq_domain *domain;
 static void __iomem *omap_irq_base;
+static int omap_nr_irqs = 96;
 
 /* Structure to save interrupt controller context */
 struct omap3_intc_regs {
@@ -170,6 +171,8 @@ static void __init omap_init_irq(u32 base, int nr_irqs,
 	if (WARN_ON(!omap_irq_base))
 		return;
 
+	omap_nr_irqs = nr_irqs;
+
 	irq_base = irq_alloc_descs(-1, 0, nr_irqs, 0);
 	if (irq_base < 0) {
 		pr_warn("Couldn't allocate IRQ numbers\n");