phy: realtek: usb: add new driver for the Realtek RTD SoC USB 2.0 PHY

phy: realtek: usb: add new driver for the Realtek RTD SoC USB 2.0 PHY

Realtek DHC (digital home center) RTD SoCs support DWC3 XHCI USB
controller. Added the driver to drive the USB 2.0 PHY transceivers.

Note: New driver,remove the port status notification on legacy USB PHY.
Use the generic PHY to notify the usb device connect and disconnect.
To avoid using these PHYs would require describing the very same
PHY using both the generic "phy" property and the deprecated "usb-phy"
property.

Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Link: https://lore.kernel.org/r/20231213031203.4911-2-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>