genirq: Remove IRQF_DISABLED from core code

Remove all code which is related to IRQF_DISABLED from the core kernel
code. IRQF_DISABLED still exists as a flag, but becomes a NOOP and
will be removed after a grace period. That way we can easily revert to
the previous behaviour by just restoring the core code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@osdl.org>
LKML-Reference: <20100326000405.991244690@linutronix.de>
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index d7e7a76..e6d2f44 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -39,7 +39,8 @@
  * These flags used only by the kernel as part of the
  * irq handling routines.
  *
- * IRQF_DISABLED - keep irqs disabled when calling the action handler
+ * IRQF_DISABLED - keep irqs disabled when calling the action handler.
+ *                 DEPRECATED. This flag is a NOOP and scheduled to be removed
  * IRQF_SAMPLE_RANDOM - irq is used to feed the random generator
  * IRQF_SHARED - allow sharing the irq among several devices
  * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur