thermal/exynos: remove unnecessary header inclusions

In multiplatform configurations, we cannot include headers
provided by only the exynos platform. Fortunately a number
of drivers that include those headers do not actually need
them, so we can just remove the inclusions.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Eduardo Valentin <eduardo.valentin@ti.com>
Cc: Zhang Rui <rui.zhang@intel.com>