Revert "x86, extable: Disable presorted exception table for now"

sortextable now works with relative entries, re-enable it.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Link: http://lkml.kernel.org/r/1335291795-26693-3-git-send-email-ddaney.cavm@gmail.comSigned-off-by: NH. Peter Anvin <hpa@zytor.com>

arch/x86/Kconfig

@@ -82,6 +82,7 @@ config X86
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select GENERIC_IOMAP
 	select DCACHE_WORD_ACCESS if !DEBUG_PAGEALLOC
+	select BUILDTIME_EXTABLE_SORT
 
 config INSTRUCTION_DECODER
 	def_bool (KPROBES || PERF_EVENTS)