net: gemini: Fix missing clk_disable_unprepare() in error path of gemini_ethernet_port_probe()

[ Upstream commit 85496a29224188051b6135eb38da8afd4c584765 ]

Fix the missing clk_disable_unprepare() before return
from gemini_ethernet_port_probe() in the error handling case.

Fixes: 4d5ae32f ("net: ethernet: Add a driver for Gemini gigabit ethernet")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>