ARM: multi_v7_defconfig: Enable TMU for exynos SoCs

Enable support for Thermal Monitoring Unit present on Exynos SoCs. This
allows detection of overheat and handling this gracefully.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>