net: phy: micrel: add Asym Pause workaround for KSZ9021

The Micrel KSZ9031 PHY may fail to establish a link when the Asymmetric
Pause capability is set. This issue is described in a Silicon Errata
(DS80000691D or DS80000692D), which advises to always disable the
capability.

Micrel KSZ9021 has no errata, but has the same issue with Asymmetric Pause.
This patch apply the same workaround as the one for KSZ9031.

Fixes: 3aed3e2a ("net: phy: micrel: add Asym Pause workaround")
Signed-off-by: Hans Andersson <hans.andersson@cellavision.se>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>