rocker: Drop pointless static qualifier

There is no need to have the 'struct rocker_desc_info *desc_info'
variable static since new value always be assigned before use it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>