ACPI: Add sysfs ABI documentation

Add initial ABI documentation for ACPI devices' sysfs interfaces.
Contacts information fields are filled with current ACPI maintainer and the
relevant authors are carbon copied.

[rjw: Use my e-mail address that's likely to be valid longer.]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index aa0fafd..95911af 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -243,6 +243,7 @@
 F:	include/linux/acpi.h
 F:	include/acpi/
 F:	Documentation/acpi
+F:	Documentation/ABI/testing/sysfs-bus-acpi
 
 ACPI FAN DRIVER
 M:	Zhang Rui <rui.zhang@intel.com>