Add extra hub_port_reset for MTK USB virtual hub

MTK's USB virtual hub is at a wrong state after a software reset. Thus
hub_port_init times out while waiting for the descriptor, causing a >4s
delay per TPU engine initialization. Adding an extra hub_port_reset seems
to put the hub back to the correct state, and cuts the response time to
<1s to get the descriptor after the reset.

Change-Id: If1e17fe2a71f49784ee0b9e8fc0b16f7d06753ec