upstream: Allow toggling of semantic checks

This patch adds -W and -E options to dtc which allow toggling on and off
of the various built in semantic checks on the tree.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit d5399197e9e0d8bad13de5c41df3b93804c0558a)

Change-Id: Ic77e49c9e3ac1048e9e33afdb73b95865ba8438b
6 files changed