ACPI: add a Kconfig option for ACPI procfs interface

Add a kconfig option CONFIG_ACPI_PROCFS to make procfs interface
a configurable attribute of ACPI.

No procfs interface is actually deprecated,
and no sysfs interface is added in this patch.

CONGI_ACPI_PROCFS is used to mark procfs interface as deprecated
once the same function is duplicated in sysfs.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 0f9d4be..1f82ceb 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -77,6 +77,16 @@
 	  Create /proc/acpi/sleep
 	  Deprecated by /sys/power/state
 
+config ACPI_PROCFS
+	bool "Procfs interface (deprecated)"
+	depends on ACPI
+	default y
+	---help---
+	  Procfs interface for ACPI is made optional for back-compatible.
+	  As the same functions are duplicated in sysfs interface
+	  and this proc interface will be removed some time later,
+	  it's marked as deprecated.
+
 config ACPI_AC
 	tristate "AC Adapter"
 	depends on X86