ax88179_178a: Check for supported Wake-on-LAN modes

The driver currently silently accepts unsupported Wake-on-LAN modes
(other than WAKE_PHY or WAKE_MAGIC) without reporting that to the user,
which is confusing.

Fixes: e2ca90c2 ("ax88179_178a: ASIX AX88179_178A USB 3.0/2.0 to gigabit ethernet adapter driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>