usb: chipidea: add imx platform driver

This patch supports only the host-mode functionality so far.

Signed-off-by: Richard Zhao <richard.zhao@freescale.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Peter Chen <peter.chen@freescale.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Felipe Balbi <balbi@ti.com>
Tested-by: Subodh Nijsure <snijsure@grid-net.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>