thinkpad-acpi: explain errors from acpi_install_notify_handler

Log more human-friendly errors instead of numeric values when
setup_acpi_notify() fails to install a notification handler.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>

drivers/platform/x86/thinkpad_acpi.c

@@ -785,8 +785,8 @@ static int __init setup_acpi_notify(struct ibm_struct *ibm)
 			       "handling %s events\n", ibm->name);
 		} else {
 			printk(TPACPI_ERR
-			       "acpi_install_notify_handler(%s) failed: %d\n",
-			       ibm->name, status);
+			       "acpi_install_notify_handler(%s) failed: %s\n",
+			       ibm->name, acpi_format_exception(status));
 		}
 		return -ENODEV;
 	}