genirq: Protect tglx from tripping over his own feet

The irq_desc.status field will either go away or renamed to
settings. Anyway we need to maintain compatibility to avoid breaking
the world and some more. While moving bits into the core, I need to
avoid that I use any of the still existing IRQ_ bits in the core code
by typos. So that file will hold the inline wrappers and some nasty
CPP tricks to break the build when typoed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/irq/settings.h b/kernel/irq/settings.h
new file mode 100644
index 0000000..610f555
--- /dev/null
+++ b/kernel/irq/settings.h
@@ -0,0 +1,7 @@
+/*
+ * Internal header to deal with irq_desc->status which will be renamed
+ * to irq_desc->settings.
+ */
+enum {
+	_IRQ_DEFAULT_INIT_FLAGS	= IRQ_DEFAULT_INIT_FLAGS,
+};