Utilities: Avoid deleting the same object twice in a row

If OriginalCount is 0 in AcpiUtUpdateRefCount (),
AcpiUtDeleteInternalObj () is invoked for the target object, which is
incorrect, because that object has been deleted once already and the
memory allocated to store it may have been reclaimed and allocated
for a different purpose by the host OS.  Moreover, a confusing debug
message following the "Reference Count is already zero, cannot
decrement" warning is printed in that case.

To fix this issue, make AcpiUtUpdateRefCount () return after finding
that OriginalCount is 0 and printing the above warning.

Link: #652
Reported-by: Mark Asselstine <mark.asselstine@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

source/components/utilities/utdelete.c

@@ -594,6 +594,7 @@ AcpiUtUpdateRefCount (
             ACPI_WARNING ((AE_INFO,
                 "Obj %p, Reference Count is already zero, cannot decrement\n",
                 Object));
+            return;
         }
 
         ACPI_DEBUG_PRINT_RAW ((ACPI_DB_ALLOCATIONS,