sunxi defconfig remove mmc clock gating

Signed-off-by: Michal Suchanek <hramrach@gmail.com>
sunxi: wemac: wait up to 4.5s for phy to power up

After PHY is powered up, it may take a significant time for the link
negotiation to complete. We need to wait for this information in
order to set the correct duplex mode and other things.

In my case (Mele A2000 connected to a gigabit switch) it takes ~1.5
seconds to negotiate link. Some people prefer to use 4.5 seconds for
the negotiation timeout:

    http://lists.denx.de/pipermail/u-boot/2009-February/048489.html

Signed-off-by: Siarhei Siamashka <siarhei.siamashka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>