ARM: dts: exynos: Add support for the touch-sensitive buttons on Midas family

Add support for the capacitive touch-sensitive buttons of the
following smartphones:
- Samsung Galaxy SIII (I9300)
- Samsung Galaxy SIII 4G (I9305)
- Samsung Galaxy Note II (N7100)
- Samsung Galaxy Note II 4G (N7105)

The keycodes correspond to markings on the phone case.

Signed-off-by: Simon Shields <simon@lineageos.org>
[GNUtoo@cyberdimension.org: Fixed keycodes, modified commit message]
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>