AHCI driver enhancement on master branch for DVD probe/test

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

    People with issues probing DVD drives over AHCI please test with
    the latest master branch and report if the problem has been resolved
    or not.  Use a verbose boot and try to capture any 'ahcix.x' lines
    if it still doesn't work.   Also please post if you previously had
    a non-working DVD drive which now works.

    This only applies to the AHCI driver the SILIcon Image driver.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>