tty: Move pty-specific set_termios() handling to pty driver

Packet mode is unique to the pty driver; move the packet mode state
change code from the generic tty ioctl handler to the pty driver.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/tty/pty.c
Simple merge

diff --cc drivers/tty/tty_ioctl.c
Simple merge