net: stmmac: remove unnecessary stmmac_mac_set() in stmmac_release()

stmmac_release() calls phylink_stop() and then goes on to call
stmmac_mac_set(, false). However, phylink_stop() will call
stmmac_mac_link_down() before returning, which will do this work.
Remove this unnecessary call.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Furong Xu <0x1207@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1trcI6-005rn8-GV@rmk-PC.armlinux.org.uk


Signed-off-by: Paolo Abeni <pabeni@redhat.com>