USB: hub: fix SS max number of ports

USB: hub: fix SS max number of ports

commit 93491ced3c87c94b12220dbac0527e1356702179 upstream.

Add define for the maximum number of ports on a SuperSpeed hub as per
USB 3.1 spec Table 10-5, and use it when verifying the retrieved hub
descriptor.

This specifically avoids benign attempts to update the DeviceRemovable
mask for non-existing ports (should we get that far).

Fixes: dbe79bbe9dcb ("USB 3.0 Hub Changes")
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
 - Add maxchild variable in hub_configure(), which was added separately upstream
 - Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>