SettingsProvider: change default battery style to portrait

- Circle animation causes redrawing of the status bar constantly
  while charging with screen on.  I measured 25-30% across 2 cores
  with circle, versus 2-5% with portrait (or any other style that
  doesn't constantly update the screen).  This causes unnecessary
  power (and therefore thermal) effects.

Change-Id: I53d58a215d7c49235b7a2b68ea8b486cde3a9fe9