net: phylink: add generic validate implementation

commit b786d2b0fcbf23f46f99c7b33f3ad52f31bf6749 from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git



commit 34ae2c09 upstream.

Add a generic validate() implementation using the supported_interfaces
and a bitmask of MAC pause/speed/duplex capabilities. This allows us
to entirely eliminate many driver private validate() implementations.

We expose the underlying phylink_get_linkmodes() function so that
drivers which have special needs can still benefit from conversion.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>