x86: cpu: Don't include the cpu driver in TPL

We don't need this driver very early in boot and it adds code size. Drop
it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 3f1f62d..6296b55 100644
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -26,7 +26,10 @@
 
 extra-$(CONFIG_$(SPL_TPL_)X86_16BIT_INIT) += resetvec.o start16.o
 
-obj-y	+= cpu.o cpu_x86.o
+obj-y	+= cpu.o
+ifndef CONFIG_TPL_BUILD
+obj-y	+= cpu_x86.o
+endif
 
 ifndef CONFIG_$(SPL_)X86_64
 AFLAGS_REMOVE_call32.o := -mregparm=3 \