SystemUI: A proposal for a new quiet hours icons

 PS2 added xxhdpi icons
 PS3 removed xxhdpi icons
Change-Id: I87e660210e2089d1bb09da47d39695bbda2889af

Conflicts:

	packages/SystemUI/res/drawable-hdpi/ic_qs_quiet_hours_off.png
	packages/SystemUI/res/drawable-hdpi/ic_qs_quiet_hours_on.png
	packages/SystemUI/res/drawable-mdpi/ic_qs_quiet_hours_off.png
	packages/SystemUI/res/drawable-mdpi/ic_qs_quiet_hours_on.png
	packages/SystemUI/res/drawable-xhdpi/ic_qs_quiet_hours_off.png
	packages/SystemUI/res/drawable-xhdpi/ic_qs_quiet_hours_on.png