Cleanup dock battery support
Show dock battery level if available
Cleanup dock battery support
frameworks: base: systemui: remove textSize from dock_battery_text

* Having this option set caused the text size to differ between
  dock_battery_text and battery_text when using the percentage
  battery mod.

Change-Id: Ifb58d4be08d2fc547fe74574dbd9d8d6bd279ede
SystemUI: Fix dock battery visual glitch

Hide dock battery views if device don't support dock battery status

Change-Id: If470e00a9afc2233865302bf3fa13367a77c6191
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>