USB: handle LPM errors during device suspend correctly

commit aa5ceae24bf8dff1d6fe87c6c4b08e69c6d33550 upstream.

The hub driver's usb_port_suspend() routine doesn't handle errors
related to Link Power Management properly.  It always returns failure,
it doesn't try to clean up the wakeup setting, (in the case of system
sleep) it doesn't try to go ahead with the port suspend regardless,
and it doesn't try to apply the new power-off mechanism.

This patch fixes these problems.

Note: Sarah fixed this patch to apply against 3.11, since the original
commit (4fae6f0fa86f92e6bc7429371b1e177ad0aaac66 "USB: handle LPM errors
during device suspend correctly") called usb_disable_remote_wakeup,
which won't be added until 3.12.

This patch should be backported to kernels as old as 3.5, that
contain the commit 8306095f "USB:
Disable USB 3.0 LPM in critical sections.".  There will be merge
conflicts, since LTM wasn't added until 3.6.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>