thunderbolt: Disable ports that are not implemented

Commit 4caf2511 ("thunderbolt: Add trivial .shutdown") exposes a bug
in the Thunderbolt driver, that frees an unallocated id, resulting in the
following spinlock bad magic bug.

[ 20.633803] BUG: spinlock bad magic on CPU#4, halt/3313
[ 20.640030] lock: 0xffff92e6ad5c97e0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[ 20.672139] Call Trace:
[ 20.675032] dump_stack+0x97/0xdb
[ 20.678950] ? spin_bug+0xa5/0xb0
[ 20.682865] do_raw_spin_lock+0x68/0x98
[ 20.687397] _raw_spin_lock_irqsave+0x3f/0x5d
[ 20.692535] ida_destroy+0x4f/0x124
[ 20.696657] tb_switch_release+0x6d/0xfd
[ 20.701295] device_release+0x2c/0x7d
[ 20.705622] kobject_put+0x8e/0xac
[ 20.709637] tb_stop+0x55/0x66
[ 20.713243] tb_domain_remove+0x36/0x62
[ 20.717774] nhi_remove+0x4d/0x58

Fix the issue by disabling ports that are enabled as per the EEPROM, but
not implemented. While at it, update the kernel doc for the disabled
field, to reflect this.

Cc: stable@vger.kernel.org
Fixes: 4caf2511 ("thunderbolt: Add trivial .shutdown")
Reported-by: Srikanth Nandamuri <srikanth.nandamuri@intel.com>
Signed-off-by: Nikunj A. Dadhania <nikunj.dadhania@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/switch.c

@@ -684,6 +684,7 @@ static int tb_init_port(struct tb_port *port)
 		if (res == -ENODEV) {
 			tb_dbg(port->sw->tb, " Port %d: not implemented\n",
 			       port->port);
+			port->disabled = true;
 			return 0;
 		}
 		return res;

drivers/thunderbolt/tb.h

@@ -186,7 +186,7 @@ struct tb_switch {
  * @cap_adap: Offset of the adapter specific capability (%0 if not present)
  * @cap_usb4: Offset to the USB4 port capability (%0 if not present)
  * @port: Port number on switch
- * @disabled: Disabled by eeprom
+ * @disabled: Disabled by eeprom or enabled but not implemented
  * @bonded: true if the port is bonded (two lanes combined as one)
  * @dual_link_port: If the switch is connected using two ports, points
  *		    to the other port.