x86: Pass correct cpu_index to ap_init()

In sipi_vector.S, cpu_index (passed as %eax) is wrongly overwritten
by the ap_init() function address. Correct it.

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

arch/x86/cpu/sipi_vector.S

@@ -190,8 +190,8 @@ load_msr:
 
 	/* c_handler(cpu_num) */
 	movl	%esi, %eax	/* cpu_num */
-	mov	c_handler, %eax
-	call	*%eax
+	mov	c_handler, %esi
+	call	*%esi
 
 	.align	4
 .globl	sipi_params