r8152: Factor out OOB link list waits

[ Upstream commit 5f71c84038d39def573744a145c573758f52a949 ]

The same for-loop check for the LINK_LIST_READY bit of an OOB_CTRL
register is used in several places. Factor these out into a single
function to reduce the lines of code.

Change-Id: I20e8f327045a72acc0a83e2d145ae2993ab62915
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Grant Grundler <grundler@chromium.org>
Acked-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: a699781c79ec ("ethtool: check device is present when getting link settings")
Signed-off-by: Sasha Levin <sashal@kernel.org>