x86, 386 removal: Remove CONFIG_CMPXCHG

All 486+ CPUs support CMPXCHG, so remove the fallback 386 support
code.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1354132230-21854-3-git-send-email-hpa@linux.intel.com
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index fdce49c..9a6775c 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -7,7 +7,7 @@
 	select PARAVIRT
 	select PARAVIRT_CLOCK
 	depends on X86_64 || (X86_32 && X86_PAE && !X86_VISWS)
-	depends on X86_CMPXCHG && X86_TSC
+	depends on X86_TSC
 	help
 	  This is the Linux Xen port.  Enabling this will allow the
 	  kernel to boot in a paravirtualized environment under the