ARM: exynos_defconfig: Enable LM90 driver

multi_v7_defconfig has it as Y already, so build it in here, too, for
consistency, and therefore build in HWMON as well.
Signed-off-by: Andreas Faerber <afaerber@suse.de>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

arch/arm/configs/exynos_defconfig

@@ -84,7 +84,8 @@ CONFIG_DEBUG_GPIO=y
 CONFIG_POWER_SUPPLY=y
 CONFIG_BATTERY_SBS=y
 CONFIG_CHARGER_TPS65090=y
-# CONFIG_HWMON is not set
+CONFIG_HWMON=y
+CONFIG_SENSORS_LM90=y
 CONFIG_THERMAL=y
 CONFIG_EXYNOS_THERMAL=y
 CONFIG_EXYNOS_THERMAL_CORE=y