mlxsw: pci: Use only one event queue

mlxsw: pci: Use only one event queue

The device supports two event queues. EQ0 is used for command interface
completion events. EQ1 is used for completion events of RDQ or SDQ.

Currently, for each EQE (event queue element), we check the queue number
and handle accordingly. More than that, for each interrupt we schedule
tasklets for both EQs. This is really ineffective, especially because of
the fact that EQ0 is used only as part of driver init/fini, when EMADs are
not available. There is no point to schedule the tasklet for it and check
each EQE.

A previous patch changed the code to poll command interface for each use of
it. It means that now there is no real reason to use EQ0, as we poll the
command interface.

Initialize only one event queue and use it as EQ1 (this is determined by
queue number). Then, for each interrupt we can schedule the tasklet only
for one queue and we do not have to check the queue number. This
simplifies the code and should improve performance. Note that polling
command interface is ok as we use it only as part of driver init/fini.

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/23d764f5c032e4c363b98590b746a4b32d2bf900.1712062203.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>