usb: dwc3-am62: Fix up wake-up configuration

Explicitly set and clear wakeup config so we don't leave anything
to chance.

Clear wakeup status on suspend so we know what caused wake up.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Tested-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>