hwmon: (lm63) Add sensor type attribute for external sensor on LM96163

On LM96163, the external temperature sensor type is configurable to
either a thermal diode or a 3904 transistor. The chip reports a wrong
temperature if misconfigured. Add writable attribute to support it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/Documentation/hwmon/lm63 b/Documentation/hwmon/lm63
index 0e695d3..8202825 100644
--- a/Documentation/hwmon/lm63
+++ b/Documentation/hwmon/lm63
@@ -69,4 +69,5 @@
 support these GPIO lines at present.
 
 The LM96163 is an enhanced version of LM63 with improved temperature accuracy
-and better PWM resolution.
+and better PWM resolution. For LM96163, the external temperature sensor type is
+configurable as CPU embedded diode(1) or 3904 transistor(2).