USB: serial: console: fix use-after-free after failed setup

Make sure to reset the USB-console port pointer when console setup fails
in order to avoid having the struct usb_serial be prematurely freed by
the console code when the device is later disconnected.

Change-Id: I4521740cfd288e745474d0de819a8304b72a2159
Git-commit: 299d7572e46f98534033a9e65973f13ad1ce9047
Git-repo: https://github.com/torvalds/linux/commit


Fixes: 73e487fd ("[PATCH] USB console: fix disconnection issues")
Cc: stable <stable@vger.kernel.org>	# 2.6.18
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Srinivasa Rao Kuppala <srkupp@codeaurora.org>