tty: serial: samsung_tty: do not abuse the struct uart_port unused fields

tty: serial: samsung_tty: do not abuse the struct uart_port unused fields

The samsung_tty driver was trying to abuse the struct uart_port by using
two "empty" bytes for its own use.  That's not ok, and was found by
removing those fields from the structure.

Move the variables into the port-specific structure, which is where
everything else for this port already is.  There is no space wasted here
as there was an empty "hole" in the structure already for these bytes.

Cc: Kukjin Kim <kgene@kernel.org>
Cc: Hyunki Koo <kkoos00@naver.com>
Cc: HYUN-KI KOO <hyunki00.koo@samsung.com>
Cc: Shinbeom Choi <sbeom.choi@samsung.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Dmitry Safonov <dima@arista.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20191217140232.GA3489190@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>