uboot-imx

usb: ehci: mxs: Add board-specific callbacks

Add board-specific callbacks for enabling/disabling port power
into the MXS EHCI controller driver. This is in-line with the
names of callbacks on other systems.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>