Revert "mlxsw: core: Add the hottest thermal zone detection"

Revert "mlxsw: core: Add the hottest thermal zone detection"

This reverts commit 53717dc55be862209e1742d3c34cfc4d9b2f33da and
commit 3cf9aa5c269528969c19c56e312b1c92d179d10b.

As discussed in the thread:

https://lore.kernel.org/all/f3c62ebe-7d59-c537-a010-bff366c8aeba@linaro.org/

the feature provided by commits 53717dc55be86 and 3cf9aa5c26952 is
actually already handled by the thermal framework via the cooling
device state aggregation, thus all this code is pointless.

The revert conflicts with the following changes:
 - 766f63865628c: thermal: Use mode helpers in drivers
 - 932907ee05ed6: mlxsw: core: Extend thermal module with per QSFP module thermal zones

These conflicts were fixed and the resulting changes are in this patch.

Both reverts are in the same change as requested by Ido Schimmel:

https://lore.kernel.org/all/Yvz7+RUsmVco3Xpj@shredder/

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Vadim Pasternak <vadimp@nvidia.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20220817153040.2464245-1-daniel.lezcano@linaro.org