net: phylink: ensure manual pause mode configuration takes effect

We have been relying on link events and mac_config() when the manual
pause modes are changed.  With recent developments, such as moving
the programming of link state to mac_link_up(), this no longer works.

To ensure that we update the MAC, we must generate a link-down followed
by a link-up event; we can do that by setting mac_link_dropped and
triggering a resolve.

Fixes: 91a208f2

 ("net: phylink: propagate resolved link config via mac_link_up()")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>