sparc64: use RCU page table freeing

Make use of the generic RCU page table freeing on Sparc64, doing so allows
for race-free software page-table walkers like gup_fast().

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index af64348..1074ddd 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -41,6 +41,7 @@
 	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	select HAVE_KRETPROBES
 	select HAVE_KPROBES
+	select HAVE_RCU_TABLE_FREE if SMP
 	select HAVE_MEMBLOCK
 	select HAVE_SYSCALL_WRAPPERS
 	select HAVE_DYNAMIC_FTRACE