x86: Make x86_init_cpus() static

There are no other implementations of this function, and boards that need it
can implement a CPU driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index 381d835..3c812e9 100644
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -688,7 +688,7 @@
 }
 #endif
 
-__weak int x86_init_cpus(void)
+static int x86_init_cpus(void)
 {
 #ifdef CONFIG_SMP
 	debug("Init additional CPUs\n");