dmatest: verbose mode

Verbose mode turns on test success messages, by default we only output
test summaries and failure results.

Also cleaned up some stray quotes, leftover from putting the result
message format string all on one line.

Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>