usb: musb: ux500: move the MUSB HDRC configuration into the driver

The MUSB HDRC configuration never changes between each of the ux500
supported platforms, so there's little point passing it though platform
data. If we set it in the driver instead, we can make good use of it
when booting with either ATAGs or Device Tree.

Cc: linux-usb@vger.kernel.org
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>