Revert "QS tiles custom background (2/2)"

This reverts commit c81a9690899db1b95121ef2bc9dfe22cbcf33068.

Conflicts:
	res/xml/quicksettings_tiles_style.xml

Change-Id: Ie83d9fd723f84b29aeb467887a8c98bc442df2e6

Conflicts:
	res/xml/quicksettings_tiles_style.xml
	src/com/android/settings/pixel/QuickSettingsTilesStyle.java