patman: Add -a option to refrain from test-applying the patches

Especially with the Linux kernel, it takes a long time (a minute or more)
to test-apply the patches, so patman becomes significantly less useful.
The only real problem that is found with this apply step is trailing spaces.
Provide a -a option to skip this step, for those working with clean patches.

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