Replace 4G icons with LTE.

I could of modified the LTE case in the network controller in order to point to new drawables,
but I simply replaced the icons for theming purposes. This should play well when a theme is applied.

Icon credits: @kroz

Conflicts:
	packages/SystemUI/res/drawable-hdpi/ic_qs_signal_4g_light.png
	packages/SystemUI/res/drawable-xhdpi/ic_qs_signal_4g_light.png