net: phy: bcm7xxx: Remove wildcard entries

Remove the two wildcard entries, they serve no purpose and will match way too
many devices, some of them being covered by the driver in
drivers/net/phy/broadcom.c. Remove the now unused bcm7xxx_dummy_config_init()
function which would produce a warning.

Fixes: b560a58c ("net: phy: add Broadcom BCM7xxx internal PHY driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>