mii: Add mii_advertise_flowctrl()

This converts flow control capabilites to an advertising mask and can
be useful in combination with mii_resolve_flowctrl_fdx().

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed