Move CONFIG_DISPLAY_CPUINFO to Makefile

If the whole code is surrounded by #ifdef(CONFIG_ ) .. #endif,
it should be moved to Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/arm/cpu/tegra-common/Makefile b/arch/arm/cpu/tegra-common/Makefile
index edfc1a8..34d5734 100644
--- a/arch/arm/cpu/tegra-common/Makefile
+++ b/arch/arm/cpu/tegra-common/Makefile
@@ -8,4 +8,5 @@
 #
 
 obj-y += lowlevel_init.o
-obj-y	+= ap.o board.o sys_info.o clock.o cache.o
+obj-y	+= ap.o board.o clock.o cache.o
+obj-$(CONFIG_DISPLAY_CPUINFO) += sys_info.o