xhci: dbgtty: use kfifo from tty_port struct

[ Upstream commit 866025f0 ]

There is no need to define one in a custom structure. The tty_port one
is free to use.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Mathias Nyman <mathias.nyman@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/20240808103549.429349-6-jirislaby@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 30c9ae5e ("xhci: dbc: honor usb transfer size boundaries.")
Signed-off-by: Sasha Levin <sashal@kernel.org>