net: stmmac: Do not request stmmaceth clock

net: stmmac: Do not request stmmaceth clock

The stmmaceth clock is specified by the slave_bus and apb_pclk clocks in
the device tree bindings for snps,dwc-qos-ethernet-4.10 compatible nodes
of this IP.

The subdrivers for these bindings will be requesting the stmmac clock
correctly at a later point, so there is no need to request it here and
cause an error message to be printed to the kernel log.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>