serial: Move carriage return before line feed for some serial drivers

In general, a carriage return needs to execute before a line feed.
The patch is to change some serial drivers based on this rule, such
as serial_mxc.c, serial_pxa.c, serial_s3c24x0.c and usbtty.c.

Signed-off-by: Alison Wang <alison.wang@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
4 files changed