hwmon: (mlxreg-fan) Fix double "Mellanox"

Remove the duplicate "Mellanox" in the help text for the Mellanox FAN
driver configuration option.

Fixes: 65afb4c8 ("hwmon: (mlxreg-fan) Add support for Mellanox FAN driver")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201005124843.26688-1-geert+renesas@glider.beSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/Kconfig

@@ -1080,7 +1080,7 @@ config SENSORS_MCP3021
 	  will be called mcp3021.
 
 config SENSORS_MLXREG_FAN
-	tristate "Mellanox Mellanox FAN driver"
+	tristate "Mellanox FAN driver"
 	depends on MELLANOX_PLATFORM
 	imply THERMAL
 	select REGMAP