thunderbolt: Move vendor specific NVM handling into nvm.c

thunderbolt: Move vendor specific NVM handling into nvm.c

As there will be more USB4 devices that support NVM firmware upgrade from
various vendors, it makes sense to split out the Intel specific NVM
image handling from the generic code. This moves the Intel specific NVM
handling into a new structure that will be matched by the device type
and the vendor ID. Do this for both routers and retimers.

This makes it easier to extend the NVM support to cover new vendors and
NVM image formats in the future.

Signed-off-by: Szuying Chen <Chloe_Chen@asmedia.com.tw>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>