ia64: move nr-irqs.h to include/generated

Avoid generating files in the now deprecated asm-ia64 dir
Simplified the logic in the Makefile when editing stuff in the area

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/arch/ia64/include/asm/irq.h b/arch/ia64/include/asm/irq.h
index 5282546..91b920fd 100644
--- a/arch/ia64/include/asm/irq.h
+++ b/arch/ia64/include/asm/irq.h
@@ -13,7 +13,7 @@
 
 #include <linux/types.h>
 #include <linux/cpumask.h>
-#include <asm-ia64/nr-irqs.h>
+#include <generated/nr-irqs.h>
 
 static __inline__ int
 irq_canonicalize (int irq)