net: phy: at803x: add resume/suspend function to qca83xx phy

Add resume/suspend function to qca83xx internal phy.
We can't use the at803x generic function as the documentation lacks of
any support for WoL regs.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>