drivers: ethernet: w5500: Add link status detection

Implemented link status detection using the W5500 built-in registers.
Added periodic link status polling, configurable via Kconfig.
Speeds up DHCPv4 from 9 seconds at best, to ~2 seconds after power-up.

Signed-off-by: Volodymyr Shymanskyy <vshymanskyi@gmail.com>
2 files changed