octeontx2-nicvf: fix ioctl callback

The mii ioctls are now handled by the ndo_eth_ioctl() callback,
not the old ndo_do_ioctl(), but octeontx2-nicvf introduced the
function for the old way.

Move it over to ndo_eth_ioctl() to actually allow calling it from
user space.

Fixes: 43510ef4 ("octeontx2-nicvf: Add PTP hardware clock support to NIX VF")
Fixes: a7605370 ("dev_ioctl: split out ndo_eth_ioctl")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>