net: phy: mdio-i2c: defer RollBall bridge probe to PHY discovery

Hi Maxime,

Thank you for the question — it revealed a gap in the commit message.

The regression turns out to affect both boot-inserted and hotplugged genuine RollBall modules. Aleksander Bajkowski confirmed that his FLYPRO SFP-10GT-CS-30M (with Aquantia AQR113C) is broken even when hotplugged — the PHY is no longer detected after 8fe125892f40.

So the root cause is not boot vs. hotplug specifically: sfp_sm_add_mdio_bus() in SFP_S_INIT gives the bridge only a 200 ms window, which is insufficient on hardware where bridge initialization takes longer, regardless of insertion timing.

Jan Hoffmann also correctly pointed out that the commit message was wrong about the state: the probe runs in SFP_S_INIT (which follows SFP_S_WAIT), not "before initialization delays."

v2 with both corrections is at:
https://lore.kernel.org/netdev/[email protected]/

Thanks,
Petr