FROMGIT: net: phy: at803x: Disable phy delay for RGMII mode

For RGMII mode, phy delay should be disabled. Add this case along
with disable delay routines.

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit cd28d1d6
https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git

)
Signed-off-by: Khasim Syed Mohammed <khasim.mohammed@linaro.org>