scripts/dtc: Update to upstream version v1.7.0-95-gbcd02b523429

Some pending overlay additions need the graph check fix.

This adds the following commits from upstream:

bcd02b523429 fdtoverlay: remove wrong singular article in a comment
84b056a89d3c checks: relax graph checks for overlays

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>