ARM: davinci: enable da8xx build concurrently with older devices

Enable da8xx devices to build concurrently with older
(traditional) DaVinci devices. Do this by defining multiple
zreladdr values and enabling AUTO_ZRELADDR to prevent
build regressions. Note that we do not enable AUTO_ZRELADDR in
da8xx_omapl_defconfig since it is meant to be removed.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>