power/supply: unify DT documentation

Currently the power supply device tree documentation is spread
in .../bindings/power_supply and .../bindings/power. This
unifies the files for chargers and battery fuel gauges in
.../bindings/power/supply and the ones for system reset/shutdown
in .../bindings/power/reset (same structure as used for the
drivers itself).
Signed-off-by: NSebastian Reichel <sre@kernel.org>

MAINTAINERS

@@ -9331,8 +9331,7 @@ M:	David Woodhouse <dwmw2@infradead.org>
 L:	linux-pm@vger.kernel.org
 T:	git git://git.infradead.org/battery-2.6.git
 S:	Maintained
-F:	Documentation/devicetree/bindings/power/
-F:	Documentation/devicetree/bindings/power_supply/
+F:	Documentation/devicetree/bindings/power/supply/
 F:	include/linux/power_supply.h
 F:	drivers/power/supply/