net: stmmac: dwmac-sun8i: use return val of readl_poll_timeout()

stable inclusion
from stable-v5.10.101
commit 87bbd78a2cd1b40a607f55e5135b222e51f27b9c
bugzilla: https://gitee.com/openeuler/kernel/issues/I5669Z

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=87bbd78a2cd1b40a607f55e5135b222e51f27b9c



--------------------------------

[ Upstream commit 9e0db41e ]

When readl_poll_timeout() timeout, we'd better directly use its return
value.

Before this patch:
[    2.145528] dwmac-sun8i: probe of 4500000.ethernet failed with error -14

After this patch:
[    2.138520] dwmac-sun8i: probe of 4500000.ethernet failed with error -110

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>