net: Use conftest to determime NAPI interface

Add compile time tests to the conftest.sh script
to determine netif_napi interface check at compile
time for the kernel being used. This is beneficial
for working with 3rd party Linux kernels that may
have back-ported upstream changes into the kernel
and so the kernel version checks do not work.

Bug 4456727
Bug 4451567

Change-Id: I7b00c3b491d778a9bf2f0d1069a5e4546b722e2a
Signed-off-by: Jason Mei <jianjunm@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3096002
Reviewed-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
(cherry picked from commit 888f248ee2)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3096946
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/pci/endpoint/functions/pci-epf-tegra-vnet.c

@@ -15,6 +15,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <nvidia/conftest.h>
+
 #include <linux/etherdevice.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
@@ -1881,8 +1883,11 @@ static int tvnet_ep_pci_epf_bind(struct pci_epf *epf)
 	tvnet->ndev = ndev;
 	SET_NETDEV_DEV(ndev, fdev);
 	ndev->netdev_ops = &tvnet_netdev_ops;
+#if defined(NV_NETIF_NAPI_ADD_WEIGHT_PRESENT) /* Linux v6.1 */
+	netif_napi_add_weight(ndev, &tvnet->napi, tvnet_ep_poll, TVNET_NAPI_WEIGHT);
+#else
 	netif_napi_add(ndev, &tvnet->napi, tvnet_ep_poll, TVNET_NAPI_WEIGHT);
-
+#endif
 	ndev->mtu = TVNET_DEFAULT_MTU;
 
 	ret = register_netdev(ndev);