net: hns3: split function hnae3_match_n_instantiate()

The function hnae3_match_n_instantiate() was called both by
initializing or uninitializing client. For uninitializing, the
return value was never used.

To make it more clear, this patch splits it to two functions,
hnae3_init_client_instance() and hnae3_uninit_client_instance().

Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>