usb: musb: da8xx: Add DT support for the DA8xx driver

This adds DT support for TI DA8xx/OMAP-L1x/AM17xx/AM18xx MUSB driver

Signed-off-by: Petr Kulhavy <petr@barix.com>
Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>