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

arch/sparc/Kconfig

@@ -36,6 +36,7 @@ config SPARC32
 	def_bool !64BIT
 	select GENERIC_ATOMIC64
 	select CLZ_TAB
+	select ARCH_THREAD_INFO_ALLOCATOR
 
 config SPARC64
 	def_bool 64BIT