hwmon: (w83627ehf) Fix negative 8-bit temperature values

Since 8-bit temperature values are now handled in 16-bit struct
members, values have to be cast to s8 for negative temperatures to be
properly handled. This is broken since kernel version 2.6.39
(commit bce26c58df86599c9570cee83eac58bdaae760e4.)

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: stable@kernel.org	# 2.6.39+
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

drivers/hwmon/w83627ehf.c

@@ -390,7 +390,7 @@ temp_from_reg(u16 reg, s16 regval)
 {
 	if (is_word_sized(reg))
 		return LM75_TEMP_FROM_REG(regval);
-	return regval * 1000;
+	return ((s8)regval) * 1000;
 }
 
 static inline u16
@@ -398,7 +398,8 @@ temp_to_reg(u16 reg, long temp)
 {
 	if (is_word_sized(reg))
 		return LM75_TEMP_TO_REG(temp);
-	return DIV_ROUND_CLOSEST(SENSORS_LIMIT(temp, -127000, 128000), 1000);
+	return (s8)DIV_ROUND_CLOSEST(SENSORS_LIMIT(temp, -127000, 128000),
+				     1000);
 }
 
 /* Some of analog inputs have internal scaling (2x), 8mV is ADC LSB */