Add ddr-regions device tree node in Tuna and Kera to optimize
boot-up time as firmware will look for this node during boot
and if it finds it early, it will save some time in bootup.
Change-Id: If3d6f3be7331870b5ecec9834de1dbebfbb6c22f
Signed-off-by: Shivendra Pratap <quic_spratap@quicinc.com>