mlxsw: pci: Remove unused counters

mlxsw: pci: Remove unused counters

The structure 'mlxsw_pci_queue' stores several counters which were consumed
via debugfs. Since commit 9a32562becd9 ("mlxsw: Remove debugfs interface"),
these counters are not used. Remove them. This makes the 'union u' and
'struct eq' redundant. Maintain 'struct cq' as it will be extended later.

Replace increasing 'q->u.eq.ev_other_count' with WARN_ON_ONCE(), as it is
used in an unreasonable case of receiving event in EQ which is not EQ0 or
EQ1. When the queues are initialized, we check number of event queues and
fail with the print "Unsupported number of queues" in case that the driver
tries to initialize more than two queues.

Signed-off-by: Amit Cohen <amcohen@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/ee9e658800aa0390e08342100bc27daff4c176c0.1712062203.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>