Revert "SystemUi: update 6bar drawables"

This reverts commit 5e58995de7386a0311e11d117711881febce292a.

Revert "frameworks/base: update 6bar drawables"

This reverts commit 862ae426846f8f9d3367d7b08d86995d656826e9.

Revert "SystemUI: 6-bar signal icon sytle option"

This reverts commit 5452ba224501efaa9409831c9f4330048a87b46d.

Change-Id: Ibfba736f5a39d435e3b18dfaff31740d0c6fb410