Correct SPL use of DISPLAY_CPUINFO

This converts 1 usage of this option to the non-SPL form, since there is
no SPL_DISPLAY_CPUINFO defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/arm/mach-rockchip/cpu-info.c

@@ -44,7 +44,7 @@ char *get_reset_cause(void)
 	return cause;
 }
 
-#if CONFIG_IS_ENABLED(DISPLAY_CPUINFO)
+#if IS_ENABLED(CONFIG_DISPLAY_CPUINFO)
 int print_cpuinfo(void)
 {
 	char *cause = get_reset_cause();