Merge branch 'mlxsw-extend-device-registers-for-line-cards-support'

Ido Schimmel says:

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mlxsw: Extend device registers for line cards support

This patch set prepares mlxsw for line cards support by extending device
registers with a slot index, which allows accessing components found on
a line card at a given slot. Currently, only slot index 0 (main board)
is used.

No user visible changes that I am aware of.
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Link: https://lore.kernel.org/r/20220411144657.2655752-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>