x86: Add a CPU init function for TPL

For TPL we only need to set up the features and identify the CPU to a
basic level. Add a function to handle that.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/cpu/i386/cpu.c

@@ -385,6 +385,14 @@ static void setup_mtrr(void)
 	}
 }
 
+int x86_cpu_init_tpl(void)
+{
+	setup_cpu_features();
+	setup_identity();
+
+	return 0;
+}
+
 int x86_cpu_init_f(void)
 {
 	if (ll_boot_init())

arch/x86/include/asm/u-boot-x86.h

@@ -34,6 +34,15 @@ int x86_cpu_init_f(void);
  */
 int x86_cpu_reinit_f(void);
 
+/**
+ * x86_cpu_init_tpl() - Do the minimum possible CPU init
+ *
+ * This just sets up the CPU features and figured out the identity
+ *
+ * @return 0 (indicating success, to mimic cpu_init_f())
+ */
+int x86_cpu_init_tpl(void);
+
 int cpu_init_f(void);
 void setup_gdt(struct global_data *id, u64 *gdt_addr);
 /*