dm: cpu: Fix print_cpuinfo() output

It was observed that current output of print_cpuinfo() on QEMU
x86 targets does not have an ending '\n', neither have a leading
'CPU:' any more. However it used to have these before.

It turns out commit c0434407 introduced a unified DM version
of print_cpuinfo() that exposed such issue on QEMU x86.

Fixes: c0434407 ("board_f: Use static print_cpuinfo if CONFIG_CPU is active")
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

common/board_f.c

@@ -187,7 +187,7 @@ static int print_cpuinfo(void)
 		return ret;
 	}
 
-	printf("%s", desc);
+	printf("CPU:   %s\n", desc);
 
 	return 0;
 }