thermal: exynos: Remove un-necessary CPU_THERMAL dependency

This patch removes the dependency on CPU_THERMAL for compiling TMU driver.
This is useful for cases when only TMU controller needs to be initialised
without cpu cooling action.

Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Acked-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>