usb: chipidea: usbmisc: rename file, struct and functions to usbmisc_imx

This driver will be used for every Freescale SoC which has this misc
memory layout to control the basic usb handling. So better name this
driver, function and struct names in a more generic way.

Reported-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>