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

diff --git a/init/Makefile b/init/Makefile
index c55eac9..7bc47ee 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -9,7 +9,10 @@
 obj-$(CONFIG_BLK_DEV_INITRD)   += initramfs.o
 endif
 obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
-obj-$(CONFIG_HAVE_GENERIC_INIT_TASK) += init_task.o
+
+ifneq ($(CONFIG_ARCH_INIT_TASK),y)
+obj-y                          += init_task.o
+endif
 
 mounts-y			:= do_mounts.o
 mounts-$(CONFIG_BLK_DEV_RAM)	+= do_mounts_rd.o