init_task: Replace CONFIG_HAVE_GENERIC_INIT_TASK

Now that all archs except ia64 are converted, replace the config and
let the ia64 select CONFIG_ARCH_INIT_TASK

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20120503085035.867948914@linutronix.de

arch/openrisc/Kconfig

@@ -17,7 +17,6 @@ config OPENRISC
 	select GENERIC_IOMAP
 	select GENERIC_CPU_DEVICES
 	select GENERIC_ATOMIC64
-	select HAVE_GENERIC_INIT_TASK
 
 config MMU
 	def_bool y