Add "fsl,imx6q-usbphy" for imx6dq and imx6dl, add
"fsl,imx6sl-usbphy" for imx6sl, and "fsl,imx23-usbphy"
is still a fallback for other strings.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>