usb: core: port: do error out if usb_autopm_get_interface() fails

usb: core: port: do error out if usb_autopm_get_interface() fails

commit 1f8b39bc99a31759e97a0428a5c3f64802c1e61d upstream.

Reviewing a fresh portion of coverity defects in USB core
(specifically CID 1458999), Alan Stern noted below in [1]:

On Tue, Feb 25, 2020 at 02:39:23PM -0500, Alan Stern wrote:
 > A revised search finds line 997 in drivers/usb/core/hub.c and lines
 > 216, 269 in drivers/usb/core/port.c.  (I didn't try looking in any
 > other directories.)  AFAICT all three of these should check the
 > return value, although a error message in the kernel log probably
 > isn't needed.

Factor out the usb_port_runtime_{resume,suspend}() changes into a
standalone patch to allow conflict-free porting on top of stable v3.9+.

[1] https://lore.kernel.org/lkml/Pine.LNX.4.44L0.2002251419120.1485-100000@iolanthe.rowland.org

Fixes: 971fcd492cebf5 ("usb: add runtime pm support for usb port device")
Cc: stable@vger.kernel.org # v3.9+
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200226175036.14946-3-erosca@de.adit-jv.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>