usb: dwc2: fix unbalanced phy control

Even when DWC2 is in (internal) suspended state, it should disable PHY
in suspend and then enable it in resume. This patch fixes unbalanced PHY
control sequence.

Tested-by: John Youn <johnyoun@synopsys.com>
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>