dtc: Revert unintentional submodule downgrade from commit 077dd74239a99

Commit 077dd74239a99 inadvertently downgraded the 'dtc' submodule,
undoing the increment added in commit 6e85fce0225f. Revert this,
returning the submodule state to where we should be.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/dtc b/dtc
index 65cc4d2748a2c2e6f27f1cf39e07a5dbabd80ebf..ec02b34c05be04f249ffaaca4b666f5246877dea 160000 (submodule)
--- a/dtc
+++ b/dtc
@@ -1 +1 @@
-Subproject commit 65cc4d2748a2c2e6f27f1cf39e07a5dbabd80ebf
+Subproject commit ec02b34c05be04f249ffaaca4b666f5246877dea