staging: gpib: lpvo_usb: Return error value from gpib_register_driver()

The function gpib_register_driver() can fail and does not return an
error value if it fails.

Return the error value if gpib_register_driver() fails. Add pr_err()
statement indicating the fail and error value.

Signed-off-by: Nihar Chaithanya <niharchaithanya@gmail.com>
Link: https://lore.kernel.org/r/20241230185633.175690-13-niharchaithanya@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: niharcy

drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c

@@ -1179,7 +1179,11 @@ static int usb_gpib_init_module(struct usb_interface *interface)
 		return rv;
 
 	if (!assigned_usb_minors) {
-		gpib_register_driver(&usb_gpib_interface, THIS_MODULE);
+		rv = gpib_register_driver(&usb_gpib_interface, THIS_MODULE);
+		if (rv) {
+			pr_err("lpvo_usb_gpib: gpib_register_driver failed: error = %d\n", rv);
+			goto exit;
+		}
 	} else {
 		/* check if minor is already registered - maybe useless, but if
 		 *  it happens the code is inconsistent somewhere