net: dsa: tag_8021q: clarify index limitation

Now that there's no restriction from the DSA core side regarding
the switch IDs and port numbers, only tag_8021q which is currently
reserving 3 bits for the switch ID and 4 bits for the port number, has
limitation for these values. Update their descriptions to reflect that.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dsa/tag_8021q.c

@@ -31,15 +31,14 @@
  *	Must be transmitted as zero and ignored on receive.
  *
  * SWITCH_ID - VID[8:6]:
- *	Index of switch within DSA tree. Must be between 0 and
- *	DSA_MAX_SWITCHES - 1.
+ *	Index of switch within DSA tree. Must be between 0 and 7.
  *
  * RSV - VID[5:4]:
  *	To be used for further expansion of PORT or for other purposes.
  *	Must be transmitted as zero and ignored on receive.
  *
  * PORT - VID[3:0]:
- *	Index of switch port. Must be between 0 and DSA_MAX_PORTS - 1.
+ *	Index of switch port. Must be between 0 and 15.
  */
 
 #define DSA_8021Q_DIR_SHIFT		10