task_allocator: Use config switches instead of magic defines

Replace __HAVE_ARCH_TASK_ALLOCATOR and __HAVE_ARCH_THREAD_ALLOCATOR
with proper config switches.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20120505150142.371309416@linutronix.de
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 022ea3a..ba667b6 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -35,6 +35,8 @@
 	select GENERIC_IOMAP
 	select GENERIC_SMP_IDLE_THREAD
 	select ARCH_INIT_TASK
+	select ARCH_TASK_STRUCT_ALLOCATOR
+	select ARCH_THREAD_INFO_ALLOCATOR
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to