remove a superfluous kconfig type definition

It's either

        bool
        default y

or

        def_bool y

but not a mixture of both.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/Kconfig

@@ -156,7 +156,6 @@ config ARCH_MTD_XIP
 	bool
 
 config GENERIC_HARDIRQS_NO__DO_IRQ
-	bool
 	def_bool y
 
 if OPROFILE