hwmon: (ltc4261) set data->valid to 0 if error

If there is an error it is better to set data->valid to 0
so the next call to ltc4261_update_device will always be
executed.

Signed-off-by: Frans Meulenbroeks <fransmeulenbroeks@gmail.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
diff --git a/drivers/hwmon/ltc4261.c b/drivers/hwmon/ltc4261.c
index 4b50601..ce52355 100644
--- a/drivers/hwmon/ltc4261.c
+++ b/drivers/hwmon/ltc4261.c
@@ -85,6 +85,7 @@
 					"Failed to read ADC value: error %d\n",
 					val);
 				ret = ERR_PTR(val);
+				data->valid = 0;
 				goto abort;
 			}
 			data->regs[i] = val;