USB: musb: remove obsolete resume-signalling comments

Remove comments about resume signalling being stopped from
GetPortStatus, something which is no longer the case.

Fixes: 8ed1fb79 ("usb: musb: finish suspend/reset work...")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>