amd-xgbe-phy: Updates to rate change complete check

Currently, the logic will loop endlessly waiting for a rate change
to complete.  Add a counter so that if the rate change signals
never indicate complete the loop will eventually exit.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>