ARM: OMAP: fix false lockdep warnings

Remove false lockdep warnings about lock recursion when declaring
IRQs as being wake-capable, by marking putting GPIO irq_desc locks
into their own class.

(Thanks to Peter Zijlstra for helping track down such a small
fix to this problem.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/gpio.c

@@ -1277,6 +1277,11 @@ static struct clk *gpio_fclks[OMAP34XX_NR_GPIOS];
 static struct clk *gpio_iclks[OMAP34XX_NR_GPIOS];
 #endif
 
+/* This lock class tells lockdep that GPIO irqs are in a different
+ * category than their parents, so it won't report false recursion.
+ */
+static struct lock_class_key gpio_lock_class;
+
 static int __init _omap_gpio_init(void)
 {
 	int i;
@@ -1450,6 +1455,7 @@ static int __init _omap_gpio_init(void)
 #endif
 		for (j = bank->virtual_irq_start;
 		     j < bank->virtual_irq_start + gpio_count; j++) {
+			lockdep_set_class(&irq_desc[j].lock, &gpio_lock_class);
 			set_irq_chip_data(j, bank);
 			if (bank_is_mpuio(bank))
 				set_irq_chip(j, &mpuio_irq_chip);