usb: pxa27x_udc driver

Adds pxa27x udc driver to support USB peripherals on pxa27x chips.

The driver is compatible with: Gadget Zero, the File Storage
gadget, and the Ethernet gadget (only in CDC subset mode).

The driver can't properly support multiple interfaces, because
of hardware bugs without possible workaround.  That means no
RNDIS support from g_ether, and no CDC ACM support in g_serial.

Signed-off-by: Robert Jarzmik <rjarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>