test/py: detect another "bad pattern" in console output
Many error situations in U-Boot print the message:
### ERROR ### Please RESET the board ###
Add this to the list of bad patterns the test system detects. One
practical advantage of this change is to detect the case where sandbox
is told to use a particular DTB file, and the file cannot be opened.
Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Simon Glass <sjg@chromium.org>