accel/amdxdna: skip destroy VFs cmd when no VFs were created

When unloading the driver, aie4_sriov_stop() unconditionally sends a
destroy VFs firmware command even when no VFs were ever created. This
causes the firmware to return an error:

  amdxdna: [drm] *ERROR* aie_send_mgmt_msg_wait: command opcode 0x20002 failed, status 0x1
  amdxdna: [drm] *ERROR* aie4_destroy_vfs: destroy vfs op failed: -22

Fix this by checking pci_num_vf() at the top of aie4_sriov_stop() and
returning early if no VFs exist.

Signed-off-by: Nishad Saraf <nishads@amd.com>

Author: NishadSaraf

drivers/accel/amdxdna/aie4_sriov.c

@@ -45,6 +45,9 @@ int aie4_sriov_stop(struct amdxdna_dev_hdl *ndev)
 	struct pci_dev *pdev = to_pci_dev(xdna->ddev.dev);
 	int ret;
 
+	if (!pci_num_vf(pdev))
+		return 0;
+
 	ret = pci_vfs_assigned(pdev);
 	if (ret) {
 		XDNA_ERR(xdna, "VFs are still assigned to VMs");