net: phy: aquantia: fix -ETIMEDOUT PHY probe failure when firmware not present

net: phy: aquantia: fix -ETIMEDOUT PHY probe failure when firmware not present

The author of the blamed commit apparently did not notice something
about aqr_wait_reset_complete(): it polls the exact same register -
MDIO_MMD_VEND1:VEND1_GLOBAL_FW_ID - as aqr_firmware_load().

Thus, the entire logic after the introduction of aqr_wait_reset_complete() is
now completely side-stepped, because if aqr_wait_reset_complete()
succeeds, MDIO_MMD_VEND1:VEND1_GLOBAL_FW_ID could have only been a
non-zero value. The handling of the case where the register reads as 0
is dead code, due to the previous -ETIMEDOUT having stopped execution
and returning a fatal error to the caller. We never attempt to load
new firmware if no firmware is present.

Based on static code analysis, I guess we should simply introduce a
switch/case statement based on the return code from aqr_wait_reset_complete(),
to determine whether to load firmware or not. I am not intending to
change the procedure through which the driver determines whether to load
firmware or not, as I am unaware of alternative possibilities.

At the same time, Russell King suggests that if aqr_wait_reset_complete()
is expected to return -ETIMEDOUT as part of normal operation and not
just catastrophic failure, the use of phy_read_mmd_poll_timeout() is
improper, since that has an embedded print inside. Just open-code a
call to read_poll_timeout() to avoid printing -ETIMEDOUT, but continue
printing actual read errors from the MDIO bus.

Fixes: ad649a1fac37 ("net: phy: aquantia: wait for FW reset before checking the vendor ID")
Reported-by: Clark Wang <xiaoning.wang@nxp.com>
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/netdev/8ac00a45-ac61-41b4-9f74-d18157b8b6bf@nvidia.com/
Reported-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Closes: https://lore.kernel.org/netdev/c7c1a3ae-be97-4929-8d89-04c8aa870209@gmx.net/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Link: https://patch.msgid.link/20240913121230.2620122-1-vladimir.oltean@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>