thermal: exynos: Remove non DT based support

Recently non DT support from Exynos platform is removed and hence
removing non DT support from the driver also. This will help in easy
maintainence.

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>