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>

kernel/irq/settings.h

@@ -5,3 +5,6 @@
 enum {
 	_IRQ_DEFAULT_INIT_FLAGS	= IRQ_DEFAULT_INIT_FLAGS,
 };
+
+#undef IRQ_INPROGRESS
+#define IRQ_INPROGRESS		GOT_YOU_MORON