The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

Fixes: b38dd98f ("net: stmmac: Add Toshiba Visconti SoCs glue driver")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NNobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Link: https://lore.kernel.org/r/20210223104803.4047281-1-weiyongjun1@huawei.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>