dfu-util allows filtering on USB device vendor:product ID by using
the -d flag (-d 0451:d022).
Such option is very handy when many DFU devices are connected to a single
host PC. This commit allows testing when above situation emerges.
Signed-off-by: NLukasz Majewski <l.majewski@majess.pl>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Tested-by: NLukasz Majewski <l.majewski@majess.pl>
Test HW - AM335x Beagle Bone Black
NOTE: Max size of file to transfer: 2MiB

Signed-off-by: NLukasz Majewski <l.majewski@samsung.com>

Various misc enhancements to dfu_gadget_test.sh:

* After every write (download), perform a write to a different file
  with different data. This ensures that the DFU buffer's content is
  replaced, so that if the read (upload) succeeds, we know that the
  correct data was actually read from the storage device, rather than
  simply being left over in the DFU buffer. This requires two alt
  setting names to be passed to the script, and a dummy data file to
  be generated by dfu_gadget_test_init.sh.

* Fix the assumption that dfu_gadget_test.sh is run from the directory
  that contains it, by cd'ing to that directory before invoking
  ./dfu_gadget_test_init.sh.

* Use $DIR$RCV_DIR consistently, rather than using plain $RCV_DIR in
  some places.

* Add 959, 961 test file sizes, to be consistent with having one
  more than and one less than all the other "round" sizes 64, 128, and
  4096.

* Remove references to $BKP_DIR from dfu_gadget_test_init.sh, since it
  isn't used.
Signed-off-by: NStephen Warren <swarren@nvidia.com>

This commit adds test scripts for testing if any commit has introduced
regression to the DFU subsystem.

It uses md5 to test if sent and received file is correct.
The test detailed description is available at README file.
Signed-off-by: NLukasz Majewski <l.majewski@samsung.com>