drivers/net/phy: introduce phy_set_supported()

This new function will allow MAC drivers to override supported
capabilities of the phy. It is required when MAC cannot handle all
speeds supported by phy.

For example phy supports up-to 1Gb connections while MAC may only work
in modes up to 100 or even 10 Mbit/sec.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/include/phy.h b/include/phy.h
index b793e90..e030c9f 100644
--- a/include/phy.h
+++ b/include/phy.h
@@ -234,6 +234,7 @@
 int phy_config(struct phy_device *phydev);
 int phy_shutdown(struct phy_device *phydev);
 int phy_register(struct phy_driver *drv);
+int phy_set_supported(struct phy_device *phydev, u32 max_speed);
 int genphy_config_aneg(struct phy_device *phydev);
 int genphy_restart_aneg(struct phy_device *phydev);
 int genphy_update_link(struct phy_device *phydev);