x86, 386 removal: Remove CONFIG_XADD

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

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1354132230-21854-4-git-send-email-hpa@linux.intel.com
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index 0761175..b0c30da 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -31,7 +31,7 @@
 	select MODULES_USE_ELF_RELA
 
 config RWSEM_XCHGADD_ALGORITHM
-	def_bool X86_XADD && 64BIT
+	def_bool 64BIT
 
 config RWSEM_GENERIC_SPINLOCK
 	def_bool !RWSEM_XCHGADD_ALGORITHM