serial: jsm: Use B0 instead of 0

Use B0 to check zero baudrate rather than literal 0.

While at it, remove extra parenthesis around CBAUD.
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220513082906.11096-6-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/jsm/jsm_cls.c

@@ -689,7 +689,7 @@ static void cls_param(struct jsm_channel *ch)
 	/*
 	 * If baud rate is zero, flush queues, and set mval to drop DTR.
 	 */
-	if ((ch->ch_c_cflag & (CBAUD)) == 0) {
+	if ((ch->ch_c_cflag & CBAUD) == B0) {
 		ch->ch_r_head = 0;
 		ch->ch_r_tail = 0;
 		ch->ch_e_head = 0;

drivers/tty/serial/jsm/jsm_neo.c

@@ -938,7 +938,7 @@ static void neo_param(struct jsm_channel *ch)
 	/*
 	 * If baud rate is zero, flush queues, and set mval to drop DTR.
 	 */
-	if ((ch->ch_c_cflag & (CBAUD)) == 0) {
+	if ((ch->ch_c_cflag & CBAUD) == B0) {
 		ch->ch_r_head = ch->ch_r_tail = 0;
 		ch->ch_e_head = ch->ch_e_tail = 0;