IB/IPoIB: Fix queue count inconsistency for PKEY child interfaces

IB/IPoIB: Fix queue count inconsistency for PKEY child interfaces

[ Upstream commit 02daec4656a9df52ce35c5226ddd8c90ed47205a ]

There are 2 ways to create IPoIB PKEY child interfaces:
1) Writing a PKEY to /sys/class/net/<ib parent interface>/create_child.
2) Using netlink with iproute.

While with sysfs the child interface has the same number of tx and
rx queues as the parent, with netlink there will always be 1 tx
and 1 rx queue for the child interface. That's because the
get_num_tx/rx_queues() netlink ops are missing and the default value
of 1 is taken for the number of queues (in rtnl_create_link()).

This change adds the get_num_tx/rx_queues() ops which allows for
interfaces with multiple queues to be created over netlink. This
constant only represents the max number of tx and rx queues on that
net device.

Fixes: 030f85e6ddc3 ("IB/ipoib: Add rtnl_link_ops support")
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Link: https://lore.kernel.org/r/f4a42c8aa43c02d5ae5559a60c3e5e0f18c82531.1670485816.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>