net: ks8851_mll uses mii interfaces

From: Randy Dunlap <randy.dunlap@oracle.com>

ks8851_mll uses mii interfaces so it needs to select MII.

ks8851_mll.c:(.text+0xf95ac): undefined reference to `generic_mii_ioctl'
ks8851_mll.c:(.text+0xf96a0): undefined reference to `mii_ethtool_gset'
ks8851_mll.c:(.text+0xf96fa): undefined reference to `mii_ethtool_sset'
ks8851_mll.c:(.text+0xf9754): undefined reference to `mii_link_ok'
ks8851_mll.c:(.text+0xf97ae): undefined reference to `mii_nway_restart'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>