thunderbolt: Enable NVM upgrade support on Intel Maple Ridge

Intel Maple Ridge supports NVM firmware upgrade with the same flows used
on previous discrete Thunderbolt contollers from Intel (such as Titan
Ridge). Advertise NVM upgrade support for Maple Ridge in icm_probe() to
expose the corresponding files in /sys/bus/thunderbolt. The NVM firmware
process was successfully tested on a system with a JHL8540 controller
(ASUS ProArt Z790-CREATOR).

Signed-off-by: Alex James <git@alextjam.es>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>