FROMGIT: net: dsa: qca8k: disable delay for RGMII mode

In RGMII mode we should not have any delay in port MAC, so disable
the delay.

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 5ecdd77c
https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git

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