serrano: Remove AGPS_USE_PSC

Change-Id: I59a652d99ca07700a31786f516f789c79bfd3481
serrano: Remove redundant settings

 * These are already the defaults
 * Also set critical battery warning to 5%

Change-Id: I898846a4ce9663372382d229a2e8f9ac22e48e15

Conflicts:
	overlay/frameworks/base/core/res/res/values/config.xml