net: stmmac: Fix max-speed being ignored on queue re-init

It's possible to have the maximum link speed being artificially limited on
the platform-specific basis. It's done either by setting up the
plat_stmmacenet_data::max_speed field or by specifying the "max-speed"
DT-property. In such cases it's required that any specific
MAC-capabilities re-initializations would take the limit into account. In
particular the link speed capabilities may change during the number of
active Tx/Rx queues re-initialization. But the currently implemented
procedure doesn't take the speed limit into account.

Fix that by calling phylink_limit_mac_speed() in the
stmmac_reinit_queues() method if the speed limitation was required in the
same way as it's done in the stmmac_phy_setup() function.

Fixes: 95201f36 ("net: stmmac: update MAC capabilities when tx queues are updated")
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Romain Gantois <romain.gantois@bootlin.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>