genirq: Add IRQ_INPROGRESS to core

We need to maintain the flag for now in both fields status and istate.
Add a CONFIG_GENERIC_HARDIRQS_NO_COMPAT switch to allow testing w/o
the status one. Wrap the access to status IRQ_INPROGRESS in a inline
which can be turned of with CONFIG_GENERIC_HARDIRQS_NO_COMPAT along
with the define.

There is no reason that anything outside of core looks at this. That
needs some modifications, but we'll get there.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 047a695..274590f 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -50,7 +50,11 @@
 #define IRQ_TYPE_PROBE		0x00000010	/* Probing in progress */
 
 /* Internal flags */
-#define IRQ_INPROGRESS		0x00000100	/* IRQ handler active - do not enter! */
+
+#ifndef CONFIG_GENERIC_HARDIRQS_NO_COMPAT
+#define IRQ_INPROGRESS		0x00000100	/* DEPRECATED */
+#endif
+
 #define IRQ_DISABLED		0x00000200	/* IRQ disabled - do not enter! */
 #define IRQ_PENDING		0x00000400	/* IRQ pending - replay on enable */
 #define IRQ_REPLAY		0x00000800	/* IRQ has been replayed but not acked yet */