thunderbolt: Allow NVM upgrade of USB4 host routers

Intel pre-USB4 host routers required the firmware connection manager to
be active in order to perform NVM firmware upgrade and for this reason
it was disabled when software connection manager is active. However,
this is not necessary for USB4 host routers as this functionality is
part of router operations that the router implements if it wants to
support this.

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