smdk4412-common: cleanup

Change-Id: If0e25e681485bbb21f7ea615093b90a5ea90f7e3
Cleanup

- Overlay isn't required and causes wifi issues.
- i930x/n710x have their own system.prop

Change-Id: I9f9ed2ac2b6ed26264390bbc37d724f794a45af8

Conflicts:
	overlay/frameworks/base/core/res/res/values/config.xml
	system.prop