hwmon: (dell-smm) Fix off-by-one error in dell_smm_is_visible()

The documentation states that on machines supporting only global
fan mode control, the pwmX_enable attributes should only be created
for the first fan channel (pwm1_enable, aka channel 0).

Fix the off-by-one error caused by the fact that fan channels have
a zero-based index.

Cc: stable@vger.kernel.org
Fixes: 1c1658058c ("hwmon: (dell-smm) Add support for automatic fan mode")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20251203202109.331528-1-W_Armin@gmx.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/dell-smm-hwmon.c

@@ -861,9 +861,9 @@ static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types
 			if (auto_fan) {
 				/*
 				 * The setting affects all fans, so only create a
-				 * single attribute.
+				 * single attribute for the first fan channel.
 				 */
-				if (channel != 1)
+				if (channel != 0)
 					return 0;
 
 				/*