net: hns3: refactor hns3 makefile to support hns3_common module

Currently we plan to refactor PF and VF cmdq module. A new file folder
hns3_common will be created to store new common APIs used by PF and VF
cmdq module. Thus the PF and VF compilation process will both depends on
the hns3_common. This may cause parallel building problems if we add a new
makefile building unit.

So this patch combined the PF and VF makefile scripts to the top level
makefile to support the new hns3_common which will be created in the next
patch.

Signed-off-by: Jie Wang <wangjie125@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>