usb: gadget: pxa25x_udc: move register definitions from arch

ixp4xx and pxa25x both use this driver and provide a slightly
different set of register definitions for it. Aside from that,
the definition in the ixp4xx-regs.h header conflicts with the
on in the pxa27x device driver when compile-testing that:

In file included from ../drivers/usb/gadget/udc/pxa27x_udc.c:37:0:
../drivers/usb/gadget/udc/pxa27x_udc.h:26:0: warning: "UDCCR" redefined
 #define UDCCR  0x0000  /* UDC Control Register */
 ^
In file included from ../arch/arm/mach-ixp4xx/include/mach/hardware.h:27:0,
                 from ../arch/arm/mach-ixp4xx/include/mach/io.h:18,
                 from ../arch/arm/include/asm/io.h:194,
                 from ../include/linux/io.h:25,
                 from ../include/linux/irq.h:24,
                 from ../drivers/usb/gadget/udc/pxa27x_udc.c:23:
../arch/arm/mach-ixp4xx/include/mach/ixp4xx-regs.h:415:0: note: this is the location of the previous definition
 #define UDCCR  IXP4XX_USB_REG(IXP4XX_USB_BASE_VIRT+0x0000)

This addresses both issues by moving all the definitions into the
pxa25x_udc driver itself. It turns out the only difference between
them was 'UDCCS_IO_ROF', and that could well be a mistake when it
was incorrectly copied from pxa25x to ixp4xx.

Acked-by: Krzysztof Halasa <khalasa@piap.pl>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Felipe Balbi <balbi@kernel.org>