ACPI / scan: Make memory hotplug driver use struct acpi_scan_handler

Make the ACPI memory hotplug driver use struct acpi_scan_handler
for representing the object used to set up ACPI memory hotplug
functionality and to remove hotplug memory ranges and data
structures used by the driver before unregistering ACPI device
nodes representing memory.  Register the new struct acpi_scan_handler
object with the help of acpi_scan_add_handler_with_hotplug() to allow
user space to manipulate the attributes of the memory hotplug
profile.

This results in a significant reduction of the drvier's code size
and removes some ACPI hotplug code duplication.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 92ed969..da808239 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -345,9 +345,8 @@
 	  the module will be called container.
 
 config ACPI_HOTPLUG_MEMORY
-	tristate "Memory Hotplug"
+	bool "Memory Hotplug"
 	depends on MEMORY_HOTPLUG
-	default n
 	help
 	  This driver supports ACPI memory hotplug.  The driver
 	  fields notifications on ACPI memory devices (PNP0C80),