Fix BSOD caused by KeWaitForMultipleObjects()

KeWaitForMultipleObjects() should use a wait block array if the
number of objects exceeds THREAD_WAIT_OBJECTS. The number of objects
PdoDestroy() waits on is 4 which exceeds the currently defined value
of that constant (which is 3).

Signed-off-by: Murtaza Ghiya <murtazg@amazon.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Merge pull request #19 from pauldu/waitblock

Fix BSOD caused by KeWaitForMultipleObjects()