Documentation: devicetree: add old and deprecated 'fixed-link'

Update the fixed-link Device Tree binding documentation to contain
information about the old and deprecated 5-digit 'fixed-link' property.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed