USB: ehci: make debug port in-use detection functional again

Debug port in-use determination must be done before the controller gets
reset the first time, i.e. before the call to ehci_setup() as of commit
1a49e2ac. That commit effectively
rendered commit 9fa5780b useless.

While moving that code around, also fix the BAR determination - the
respective capability field is a 3- rather than a 2-bit one -, and use
PCI_CAP_ID_DBG instead of the literal 0x0a.

It's unclear to me whether the debug port functionality is important
enough to warrant fixing this in stable kernels too.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>