Fix the wrong description of the SAI_VLAN_STACK_ATTR_VLAN_APPLIED_PRI…

… in HLD

doc/SAI-Proposal-VlanStack-QinQ.md

@@ -42,7 +42,7 @@ __Figure 4: Vlan Stack SAI Pipeline__
 | ------------- | ---------------------------------------------- | ------------------------------- |
 | VLAN Stacking | SAI_VLAN_STACK_ATTR_STAGE                      | At which packet flow direction the action should take effect. Ingress or Egress    |
 |               | SAI_VLAN_STACK_ATTR_ACTION                     | Include SWAP, PUSH and POP operation    |
-|               | SAI_VLAN_STACK_ATTR_VLAN_APPLIED_PRI           | Rule priority from low to high can assign this from 0 to 7. If a packet can match multiple vlan stacking rule, only the highest priority rule will take effect.   |
+|               | SAI_VLAN_STACK_ATTR_VLAN_APPLIED_PRI           | The "priority" of the new VLAN tag. Default value is 0xFF which will inherit the original vlan tag priority.   |
 |               | SAI_VLAN_STACK_ATTR_ORIGINAL_VLAN_ID      | Has "outer" and "inner" attribute. Used to match the processing packet dot1q header. The vlan stacking rule only take effect if the dot1q header VLAN_ID match this setting. At least one attribute should be set.   |
 |               | SAI_VLAN_STACK_ATTR_PORT                       | Target port ID at which the vlan stacking will take effect   |
 |               | SAI_VLAN_STACK_ATTR_APPLIED_VLAN_ID            | New vlan ID for the vlan stacking. Has "outer" and "inner" attribute. User can specify where the vlan stacking rule should take effect over the packet. If the ACTION is POP, this attribute will not take effect   |