[ Upstream commit e49505f7255be8ced695919c08a29bf2c3d79616 ]

Both bcm_sf2_sw_indir_rw and mdiobus_write_nested could fail, so let's
return their error codes upstream.
Signed-off-by: NKangjie Lu <kjlu@umn.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>