ice: Prevent probing virtual functions

The userspace utility "driverctl" can be used to change/override the
system's default driver choices. This is useful in some situations
(buggy driver, old driver missing a device ID, trying a workaround,
etc.) where the user needs to load a different driver.

However, this is also prone to user error, where a driver is mapped
to a device it's not designed to drive. For example, if the ice driver
is mapped to driver iavf devices, the ice driver crashes.

Add a check to return an error if the ice driver is being used to
probe a virtual function.

Fixes: 837f08fd ("ice: Add basic driver framework for Intel(R) E800 Series")
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_main.c

@@ -4194,6 +4194,11 @@ ice_probe(struct pci_dev *pdev, const struct pci_device_id __always_unused *ent)
 	struct ice_hw *hw;
 	int i, err;
 
+	if (pdev->is_virtfn) {
+		dev_err(dev, "can't probe a virtual function\n");
+		return -EINVAL;
+	}
+
 	/* this driver uses devres, see
 	 * Documentation/driver-api/driver-model/devres.rst
 	 */