ANDROID: db845c: Enable RB3Gen2 drivers and DTB

RB3Gen2 is the new device being added in LKFT for testing
to compensate for aging RB3 and RB5 in the lab.

This device support will be added in the existing
db845c-userdebug build target upstream.

Bug: 146449535
Change-Id: I57a55a1b810a7b1aa0f402832670456f3f97c9cc
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
[jstultz: Did the buildifier cleanup]
Signed-off-by: John Stultz <jstultz@google.com>