net: hns3: remove unused head file in hnae3.c

net: hns3: remove unused head file in hnae3.c

BugLink: https://bugs.launchpad.net/bugs/1787477
linux/slab.h is not used in hnae3.h, this patch removes it.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit fe589e0454b3a18ab9aaddaa8b4925e629d46792)
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>