Updates to "usbtest" driver:

  * Improve some diagnostics.  One path that never generated diagnostics
    before should now generate two ... unless you hit a GCC bug that
    all my compilers seem to have, go figure.

  * Add suspend/resume support, so this behaves when the Linux host
    being used for testing suspends.

  * Don't test the "zero byte ep0 read" case unless real-world relevance
    for the testing is is irrelevant.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>