vDPA/ifcvf: Fix pci_read_config_byte() return code handling

ifcvf_init_hw() uses pci_read_config_byte() that returns
PCIBIOS_* codes. The error handling, however, assumes the codes are
normal errnos because it checks for < 0.
Convert the error check to plain non-zero check.

Fixes: 5a2414b ("virtio: Intel IFC VF driver for VDPA")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Message-Id: <20241017013812.129952-1-yuancan@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Zhu Lingshan <lingshan.zhu@kernel.org>

drivers/vdpa/ifcvf/ifcvf_base.c

@@ -108,7 +108,7 @@ int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *pdev)
 	u32 i;
 
 	ret = pci_read_config_byte(pdev, PCI_CAPABILITY_LIST, &pos);
-	if (ret < 0) {
+	if (ret) {
 		IFCVF_ERR(pdev, "Failed to read PCI capability list\n");
 		return -EIO;
 	}