usbip: usbip_host: run rebind from exit when module is removed

usbip: usbip_host: run rebind from exit when module is removed

BugLink: http://bugs.launchpad.net/bugs/1782846
commit 7510df3f29d44685bab7b1918b61a8ccd57126a9 upstream.

After removing usbip_host module, devices it releases are left without
a driver. For example, when a keyboard or a mass storage device are
bound to usbip_host when it is removed, these devices are no longer
bound to any driver.

Fix it to run device_attach() from the module exit routine to restore
the devices to their original drivers. This includes cleanup changes
and moving device_attach() code to a common routine to be called from
rebind_store() and usbip_host_exit().

Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>