net: phy: Move linkmode helpers to somewhere public

phylink has some useful helpers to working with linkmode bitmaps.
Move them to there own header so other code can use them.

Signed-off-by: Andrew Lunn <[email protected]>
Acked-by: Florian Fainelli <[email protected]>
Reviewed-by: Maxime Chevallier <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
4 files changed