[BATTERY] Universal power supply class (was: battery class)

This class is result of "external power" and "battery" classes merge,
as suggested by David Woodhouse. He also implemented uevent support.

Here how userspace seeing it now:

    	# ls /sys/class/power\ supply/
    	ac  main-battery  usb

    	# cat /sys/class/power\ supply/ac/type
    	AC

    	# cat /sys/class/power\ supply/usb/type
    	USB

    	# cat /sys/class/power\ supply/main-battery/type
    	Battery

    	# cat /sys/class/power\ supply/ac/online
    	1

    	# cat /sys/class/power\ supply/usb/online
    	0

    	# cat /sys/class/power\ supply/main-battery/status
    	Charging

    	# cat /sys/class/leds/h5400\:red-left/trigger
    	none h5400-radio timer hwtimer ac-online usb-online
    	main-battery-charging-or-full [main-battery-charging]
    	main-battery-full

Signed-off-by: Anton Vorontsov <cbou@mail.ru>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/drivers/Makefile b/drivers/Makefile
index adad2f3..503d825 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -61,6 +61,7 @@
 obj-$(CONFIG_RTC_LIB)		+= rtc/
 obj-y				+= i2c/
 obj-$(CONFIG_W1)		+= w1/
+obj-$(CONFIG_POWER_SUPPLY)	+= power/
 obj-$(CONFIG_HWMON)		+= hwmon/
 obj-$(CONFIG_PHONE)		+= telephony/
 obj-$(CONFIG_MD)		+= md/