The old names are defined only if the cpp symbol
IMX_NEEDS_DEPRECATED_SYMBOLS exists, which is defined (for now) for all
files below arch/arm/mach-mx1.

This was done earlier for mx2 and mx3, too.

USBD_INT0 is for now defined unconditionally to prevent breaking
drivers/usb/gadget/imx_udc.

While at it use IMX_IO_ADDRESS to define MX1_IO_ADDRESS which
adds a cast to the IO_ADDRESS macro fixing many warnings like

	arch/arm/mach-mx1/generic.c:51: warning: passing argument 1 of 'mxc_init_irq' makes pointer from integer without a cast

.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>