tty: serial: jsm: remove redundant pointer ts

Pointer ts is assigned a value that is never read, ts is therefore
redundant and can be removed. Cleans up clang warning:

drivers/tty/serial/jsm/jsm_tty.c:285:2: warning: Value stored to 'ts'
is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>