amd-xgbe: Delay AN timeout during KR training

AN restart triggered during KR training not only aborts the KR training
process but also move the HW to unstable state. Driver has to wait upto
500ms or until the KR training is completed before restarting AN cycle.

Fixes: 7c12aa08 ("amd-xgbe: Move the PHY support into amd-xgbe")
Co-developed-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
Acked-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>