net/spnic: Remove spnic driver.

Ramaxel inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4ZR0O


CVE: NA

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There are some issues of the driver that cannot be fixed now.
The driver is not good enough for the LTS quality requirements
of openEuler，so remove it.

Signed-off-by: Yanling Song <songyl@ramaxel.com>
Reviewed-by: Yang Gan <yanggan@ramaxel.com>
Acked-by: Xie Xiuqi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>