The existing i.MX chipidea support can be used for i.MX28 as well. The
main difference is that the i.MX28 doesn't have a usbmisc unit, so the
bulk of this patch makes this unit optional in the driver.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

This phy is found on i.MX6 and i.MX23/28. Currently tested only on i.MX6.
For now we take the easy way out. The phy is enabled upon registration.
More elaborated handling can be added later.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

For proper USB function the usbmisc registers have to be initialized.
This patch adds a driver which matches for the usbmisc registers. This
driver is called from a new driver which binds to the USB ports to
configure the misc registers. After that the driver registers the EHCI
driver and an ULPI transceiver if necessary. Currently only host mode
is supported, but device support can be added later.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>