usb: typec: tcpm: usb: typec: tcpm: Fix a signedness bug in tcpm_fw_get_caps()

The "port->typec_caps.data" and "port->typec_caps.type" variables are
enums and in this context GCC will treat them as an unsigned int so they
can never be less than zero.

Fixes: ae8a2ca8

 ("usb: typec: Group all TCPCI/TCPM code together")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20191001120117.GA23528@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>