usb: chipidea: usbmisc: add post handling and errata fix for mx25

This adds a post handling routine which is called after
ci13xxx_add_device was called. The first user is the mx25, which has to
disable the external-vbus-divider after the udc has started.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
[Alex: also fixed a signed one-bit bitfield a whitespace error and yet
 another set of line-too-long and void pointer casting errors]
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>