mlxsw: reg: Fix a typo in a group heading

There is no such thing as "traffic group". The group that this is a heading
of is "per traffic class counters". Fix the heading.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlxsw/reg.h

@@ -5371,7 +5371,7 @@ MLXSW_ITEM64(reg, ppcnt, tx_pause_duration,
 MLXSW_ITEM64(reg, ppcnt, tx_pause_transition,
 	     MLXSW_REG_PPCNT_COUNTERS_OFFSET + 0x70, 0, 64);
 
-/* Ethernet Per Traffic Group Counters */
+/* Ethernet Per Traffic Class Counters */
 
 /* reg_ppcnt_tc_transmit_queue
  * Contains the transmit queue depth in cells of traffic class