omap1: Simplify use of omap_irq_flags

Commit 03a9e51261
(omap1: Use asm_irq_flags for entry-macro.S) added support
for multi-omap builds with addition of the omap_irq_flags.

Commit 9f9605c2ed
(omap2+: Fix unused variable warning for omap_irq_base)
simplified omap2+ entry-macro.S by moving omap_irq_flags
out of entry-macro.S.

Simplify omap1 entry-macro.S in a similar way to keep the
code consistent. Based on a similar earlier patch for omap2+
by Russell King <rmk+kernel@arm.linux.org.uk>.

Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap1/irq.c

@@ -57,6 +57,7 @@ struct omap_irq_bank {
 	unsigned long wake_enable;
 };
 
+u32 omap_irq_flags;
 static unsigned int irq_bank_count;
 static struct omap_irq_bank *irq_banks;
 
@@ -176,7 +177,6 @@ static struct irq_chip omap_irq_chip = {
 
 void __init omap_init_irq(void)
 {
-	extern unsigned int omap_irq_flags;
 	int i, j;
 
 #if defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP850)