igc: Fix double reset adapter triggered from a single taprio cmd

[ Upstream commit b9e7fc0a ]

Following the implementation of "igc: Add TransmissionOverrun counter"
patch, when a taprio command is triggered by user, igc processes two
commands: TAPRIO_CMD_REPLACE followed by TAPRIO_CMD_STATS. However, both
commands unconditionally pass through igc_tsn_offload_apply() which
evaluates and triggers reset adapter. The double reset causes issues in
the calculation of adapter->qbv_count in igc.

TAPRIO_CMD_REPLACE command is expected to reset the adapter since it
activates qbv. It's unexpected for TAPRIO_CMD_STATS to do the same
because it doesn't configure any driver-specific TSN settings. So, the
evaluation in igc_tsn_offload_apply() isn't needed for TAPRIO_CMD_STATS.

To address this, commands parsing are relocated to
igc_tsn_enable_qbv_scheduling(). Commands that don't require an adapter
reset will exit after processing, thus avoiding igc_tsn_offload_apply().

Fixes: d3750076

 ("igc: Add TransmissionOverrun counter")
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Mor Bar-Gabay <morx.bar.gabay@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://patch.msgid.link/20240730173304.865479-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>