Since commit 4c0d2e96 ("net: phy: consider that suspend2ram may cut
off PHY power"), phy_init_hw() invokes both, the ->config_init() and
->config_intr() callbacks.

In the SMSC PHY driver, the latter acknowledges stale interrupts, hence
there's no longer a need to acknowledge them in the former as well.

There are no other callers of ->config_init() besides phy_init_hw().

Drop the redundant code.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/0254edf48bddc96c6248c4414043a3699e94614a.1655716767.git.lukas@wunner.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>