net/hinic: replace spinlock with mutex

net/hinic: replace spinlock with mutex

Using spin lock to protect critical resources
of sending mgmt messages. This will make high
CPU usage for rte_delay_ms when sending mgmt
messages frequently. We can use mutex to protect
the critical resources and usleep to reduce CPU
usage while keep functioning properly.

Signed-off-by: Ziyang Xuan <xuanziyang2@huawei.com>