alpha: add GENERIC_HARDIRQS_NO__DO_IRQ to Kconfig

Acked-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>

arch/alpha/Kconfig

@@ -68,6 +68,9 @@ config GENERIC_IOMAP
 	bool
 	default n
 
+config GENERIC_HARDIRQS_NO__DO_IRQ
+	def_bool y
+
 config GENERIC_HARDIRQS
 	bool
 	default y