alpha: in_irq() cleanup

Replace the obsolete and ambiguos macro in_irq() with new
macro in_hardirq().
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>

arch/alpha/kernel/process.c

@@ -134,7 +134,7 @@ common_shutdown_1(void *generic_ptr)
 #ifdef CONFIG_DUMMY_CONSOLE
 		/* If we've gotten here after SysRq-b, leave interrupt
 		   context before taking over the console. */
-		if (in_irq())
+		if (in_hardirq())
 			irq_exit();
 		/* This has the effect of resetting the VGA video origin.  */
 		console_lock();