net: hns3: fix a bug caused by udelay

udelay() in driver may always occupancy processor. If there is only
one cpu in system, the VF driver may initialize fail when insmod
PF and VF driver in the same system. This patch use msleep() to free
cpu when VF wait PF message.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>