The "IUDMA" engine used by bcm63xx_enet is also used by other blocks,
such as the USB 2.0 device.  Move the definitions into a common file so
that they do not need to be duplicated in each driver.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/4082/Signed-off-by: NJohn Crispin <blogic@openwrt.org>