thermal: exynos: Support thermal tripping

TMU urgently sends active-high signal (thermal trip) to PMU, and thermal
tripping by hardware logic. Thermal tripping means that PMU cuts off the
whole power of SoC by controlling external voltage regulator.

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: Jonghwan Choi <jhbird.choi@samsung.com>
Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>