net: ag71xx: call phylink_disconnect_phy if ag71xx_hw_enable() fail in ag71xx_open()

net: ag71xx: call phylink_disconnect_phy if ag71xx_hw_enable() fail in ag71xx_open()

If ag71xx_hw_enable() fails, call phylink_disconnect_phy() to clean up.
And if phylink_of_phy_connect() fails, nothing needs to be done.
Compile tested only.

Fixes: 892e09153fa3 ("net: ag71xx: port to phylink")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20221114095549.40342-1-liujian56@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>