Add Sibon wallpapers

Default wallpaper is set to a7_bw.

Issue: FP2P-311
Issue: FP2N-196
Change-Id: I52983e696cc246ccd7d0ae361d6f7b69835d471d
Depends-On: I4f3856bdc3d9545bf0f0883e8479548ea7650d6a
3 files changed
tree: fc1cd21c8bb67aec6eead9a79aa80bebbfe77220
  1. overlay/
  2. device-vendor.mk