Currently, in Spectrum-2 and above, time stamps are extracted from the CQE
into the time stamp fields in 'struct mlxsw_skb_cb', only when the CQE
time stamp type is UTC. The time stamps are read directly from the CQE and
software can get the time stamp in UTC format using CQEv2.

From Spectrum-4, the time stamps that are read from the CQE are allowed
to be also from MIRROR_UTC type.

Therefore, we get a warning [1] from the driver that the time stamp fields
were not set, when LLDP control packet is sent.

Allow the time stamp type to be MIRROR_UTC and set the time stamp in this
case as well.

[1]
 WARNING: CPU: 11 PID: 0 at drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c:1409 mlxsw_sp2_ptp_hwtstamp_fill+0x1f/0x70 [mlxsw_spectrum]
[...]
 Call Trace:
  <IRQ>
  mlxsw_sp2_ptp_receive+0x3c/0x80 [mlxsw_spectrum]
  mlxsw_core_skb_receive+0x119/0x190 [mlxsw_core]
  mlxsw_pci_cq_tasklet+0x3c9/0x780 [mlxsw_pci]
  tasklet_action_common.constprop.0+0x9f/0x110
  __do_softirq+0xbb/0x296
  irq_exit_rcu+0x79/0xa0
  common_interrupt+0x86/0xa0
  </IRQ>
  <TASK>

Fixes: 47354021 ("mlxsw: spectrum: Extend to support Spectrum-4 ASIC")
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/bcef4d044ef608a4e258d33a7ec0ecd91f480db5.1692268427.git.petrm@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>