ARM: at91: Replace uses of virt_to_phys with __pa_symbol

The PM code wrongly uses virt_to_phys() instead of __pa_symbol() and was
not updated by commit 64fc2a94 ("ARM: 8641/1: treewide: Replace uses of
virt_to_phys with __pa_symbol") because it was not yet in tree.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>

arch/arm/mach-at91/pm.c

@@ -533,8 +533,8 @@ static void __init at91_pm_backup_init(void)
 	}
 
 	pm_bu->suspended = 0;
-	pm_bu->canary = virt_to_phys(&canary);
-	pm_bu->resume = virt_to_phys(cpu_resume);
+	pm_bu->canary = __pa_symbol(&canary);
+	pm_bu->resume = __pa_symbol(cpu_resume);
 
 	return;