usb: dwc3: core: fix PHY handling during suspend

we need to power off the PHY during suspend and
power it back on during resume.

Signed-off-by: Felipe Balbi <balbi@kernel.org>
[nsekhar@ti.com: fix call to usb_phy_set_suspend() in dwc3_suspend()]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>