Update resource descriptor handling

This change restores the change introduced by commit 23b5bbe and
adds a comment concerning resource descriptor buffers that extend
beyond the END_TAG descriptor.

source/components/utilities/utresrc.c

@@ -604,9 +604,11 @@ AcpiUtWalkAmlResources (
     ACPI_FUNCTION_TRACE (UtWalkAmlResources);
 
 
-    /* The absolute minimum resource template is one EndTag descriptor */
-
-    if (AmlLength < sizeof (AML_RESOURCE_END_TAG))
+    /*
+     * The absolute minimum resource template is one EndTag descriptor.
+     * However, we will treat a lone EndTag as just a simple buffer.
+     */
+    if (AmlLength <= sizeof (AML_RESOURCE_END_TAG))
     {
         return_ACPI_STATUS (AE_AML_NO_RESOURCE_END_TAG);
     }
@@ -677,8 +679,10 @@ AcpiUtWalkAmlResources (
                 *Context = Aml;
             }
 
-            /* Normal exit */
-
+            /*
+             * Normal exit. Note: We allow the buffer to be larger than
+             * the resource template, as long as the END_TAG exists.
+             */
             return_ACPI_STATUS (AE_OK);
         }