tty: serial: jsm: jsm_cls: Remove unused variable 'discard'

Fixes the following W=1 kernel build warning(s):

drivers/tty/serial/jsm/jsm_cls.c: In function ‘cls_copy_data_from_uart_to_queue’:
drivers/tty/serial/jsm/jsm_cls.c:400:7: warning: variable ‘discard’ set but not used [-Wunused-but-set-variable]

Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Jiri Slaby <[e-mail]>
Cc: [e-mail]
Signed-off-by: Lee Jones <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/jsm/jsm_cls.c

···
 		 * which in this case is the break signal.
 		 */
 		if (linestatus & error_mask)  {
-			u8 discard;
-
 			linestatus = 0;
-			discard = readb(&ch->ch_cls_uart->txrx);
+			readb(&ch->ch_cls_uart->txrx);
 			continue;
 		}