WallpaperPicker: use 1440p images when screen width is greater than 1080

* Many device with odd resolutions, but still having a width
  greater than 1080, will benefit from these. This also fixes tablets
  which often have widths of 2560 who would want these higher res
  versions.

Change-Id: I9a1ce7851634e515ae3f4afe78867f90fe7fb6af