The driver uses hardwire MMIO addresses instead of the data
that is passed in device tree. Change it over to only
hardcode the register offset values and allow compile-testing.

Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
Tested-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>