usb: cdns2: Fix controller reset issue

commit e2940928 upstream.

Patch fixes the procedure of resetting controller.
The CPUCTRL register is write only and reading returns 0.
Waiting for reset to complite is incorrect.

Fixes: 3eb1f1ef ("usb: cdns2: Add main part of Cadence USBHS driver")
cc: stable@vger.kernel.org
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Link: https://lore.kernel.org/r/PH7PR07MB9538D56D75F1F399D0BB96F0DD922@PH7PR07MB9538.namprd07.prod.outlook.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>