thermal: samsung: Add TMU support for Exynos5420 SoCs

Exynos5420 has 5 TMU channels, the TRIMINFO register is
misplaced for TMU channels 2, 3 and 4
TRIMINFO at 0x1006c000 contains data for TMU channel 3
TRIMINFO at 0x100a0000 contains data for TMU channel 4
TRIMINFO at 0x10068000 contains data for TMU channel 2

This patch
1 Adds the neccessary register changes and arch information
   to support Exynos5420 SoCs.
2. Handles the gate clock for misplaced TRIMINFO register
3. Updates the Documentation at
   Documentation/devicetree/bindings/thermal/exynos-thermal.txt

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Acked-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>