tty: serial: make sport_uart_ops static and const

Make this const as it is only stored in the const field 'ops' of an
uart_port structure. It is not referenced in any other file and therefore
make it static too.

Done using Coccinelle.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>