all other drivers using Synopsys IPs with DT
have a compatible of snps,$driver, in order
to add consistency, we are switching over to
snps,dwc3 but keeping synopsys,dwc3 in the core
driver to maintain backwards compatibility.

New DTS bindings should NOT use synopsys,dwc3.
Signed-off-by: NFelipe Balbi <balbi@ti.com>

Added dt support for dwc3 core and update the documentation with
device tree binding information. Getting a PHY is now done using
devm_usb_get_phy_by_phandle() for dt boot.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>