percpu: build first chunk allocators selectively

There's no need to build unused first chunk allocators in.  Define
CONFIG_NEED_PER_CPU_*_FIRST_CHUNK and let archs enable them
selectively.

Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e06b2ee..f7ac272 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -150,6 +150,16 @@
 config HAVE_SETUP_PER_CPU_AREA
 	def_bool y
 
+config NEED_PER_CPU_EMBED_FIRST_CHUNK
+	def_bool y
+
+config NEED_PER_CPU_PAGE_FIRST_CHUNK
+	def_bool y
+
+config NEED_PER_CPU_LPAGE_FIRST_CHUNK
+	def_bool y
+	depends on NEED_MULTIPLE_NODES
+
 config HAVE_CPUMASK_OF_CPU_MAP
 	def_bool X86_64_SMP