usb: dwc2: gadget: Replace phyif with phy_utmi_width

The phy utmi width information is already set in hsotg params,
phyif is only used in few places and I don't see any reason to
not use hsotg's params.

Moreover the utmi width was being forced to 16 bits by platform
initialization which doesn't take in account HW configuration.

Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Jules Maselbas <jmaselbas@kalray.eu>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>