take declarations of enable_irq() et.al. to linux/interrupt.h

Now that the last inlined instances are gone, all that is left to do
is turning disable_irq_nosync on arm26 and m68k from defines to aliases
and we are all set - we can make these externs in linux/interrupt.h
uncoditional and kill remaining instances in asm/irq.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 5323f62..0a3c2eb 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -120,11 +120,11 @@
 # define local_irq_enable_in_hardirq()	local_irq_enable()
 #endif
 
-#ifdef CONFIG_GENERIC_HARDIRQS
 extern void disable_irq_nosync(unsigned int irq);
 extern void disable_irq(unsigned int irq);
 extern void enable_irq(unsigned int irq);
 
+#ifdef CONFIG_GENERIC_HARDIRQS
 /*
  * Special lockdep variants of irq disabling/enabling.
  * These should be used for locking constructs that