net: phy: remove genphy_no_soft_reset

Since 6e2d85ec ("net: phy: Stop with excessive soft reset")
we don't need genphy_no_soft_reset() any longer. Not setting
callback soft_reset results in a no-op now.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>