feat(esp_eth): Enable EEE (802.3az) on DM9051 (IDFGH-15497)

[bmork]

Significant power savings on a 100baseT link.

Description

This unconditionally enables EEE on DM9051. The resulting power savings are around 200 mW on a 100baseT link.

Related

Testing

Briefly run tested on a PoE powered ESP32C3 using a DM9051, using the PoE switch to measure total power consumption for the module.

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