i386, x86-64: show that CONFIG_HOTPLUG_CPU is required for suspend on SMP

It's not sufficiently documented that CONFIG_HOTPLUG_CPU is required for
suspend/hibernation on SMP.

Point out the non-obvious.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index c2d54b8..8770a5d 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -891,7 +891,7 @@
 	  Don't change this unless you know what you are doing.
 
 config HOTPLUG_CPU
-	bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
+	bool "Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL)"
 	depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
 	---help---
 	  Say Y here to experiment with turning CPUs off and on, and to