uboot-imx

patman: Allow tests to run even if patman is in the path

Several of the patman doctests assume that patman was run with:
  ./patman

Fix them so that they work even if patman is run with just "patman"
(because patman is in the path).

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>