core: Improve LPM support

 * Larger last_kmsg buffer in the charger log for debugging.
 * Load /init.lpm.rc in order to externalize charger setup.
 * Add support for Samsung's LPM reset reason.

Change-Id: I38cd63f7aa05685d2075d2568faf2f94f8440c88

Conflicts:
	rootdir/init.rc