arm64: defconfig: Enable exynos thermal config

This patch enables Exynos thermal and related configs for the
TMU found on Exynos7 SoC. This also enables thermal emulation
mode to test trip points.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>