net: phy: stop exporting phy_queue_state_machine

phy_queue_state_machine() isn't used outside phy.c,
so stop exporting it.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/16986d3d-7baf-4b02-a641-e2916d491264@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>