dts: atmel: sam0: Clean up devicetree

[nandojve]

Is your enhancement proposal related to a problem? Please describe.
The Atmel sam0 devicetree have been modified by many developers over the years. All those changes creating different patterns which difficult read and changes. This requires a clean-up to make it better to develop.

Describe the solution you'd like

• Harmonizing: Try to establish a pattern to list the properties on devicetree nodes.
• clean-up: Remove duplicate entries in favor to inherit a common base.