[PATCH] solve config broken: undefined reference to `online_page'

Memory hotplug code of i386 adds memory to only highmem.  So, if
CONFIG_HIGHMEM is not set, CONFIG_MEMORY_HOTPLUG shouldn't be set.
Otherwise, it causes compile error.

In addition, many architecture can't use memory hotplug feature yet.  So, I
introduce CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 3bb221d..5fa3c67 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -794,6 +794,9 @@
 
 endmenu
 
+config ARCH_ENABLE_MEMORY_HOTPLUG
+	def_bool y
+	depends on HIGHMEM
 
 menu "Power management options (ACPI, APM)"
 	depends on !X86_VOYAGER
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index a56df7b..5faacbb 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -271,6 +271,9 @@
 	  can be controlled through /sys/devices/system/cpu/cpu#.
 	  Say N if you want to disable CPU hotplug.
 
+config ARCH_ENABLE_MEMORY_HOTPLUG
+	def_bool y
+
 config SCHED_SMT
 	bool "SMT scheduler support"
 	depends on SMP
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e922a88..e2e9df3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -618,6 +618,9 @@
 
 	  Say N if you are unsure.
 
+config ARCH_ENABLE_MEMORY_HOTPLUG
+	def_bool y
+
 config KEXEC
 	bool "kexec system call (EXPERIMENTAL)"
 	depends on PPC_MULTIPLATFORM && EXPERIMENTAL
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index ccc4a7f..9103984 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -370,6 +370,8 @@
 		can be controlled through /sys/devices/system/cpu/cpu#.
 		Say N if you want to disable CPU hotplug.
 
+config ARCH_ENABLE_MEMORY_HOTPLUG
+	def_bool y
 
 config HPET_TIMER
 	bool