ARC: Fix misspellings in comments.

Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index af7a2db..a444be6 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -149,7 +149,7 @@
  * Since xchg() doesn't always do that, it would seem that following defintion
  * is incorrect. But here's the rationale:
  *   SMP : Even xchg() takes the atomic_ops_lock, so OK.
- *   LLSC: atomic_ops_lock are not relevent at all (even if SMP, since LLSC
+ *   LLSC: atomic_ops_lock are not relevant at all (even if SMP, since LLSC
  *         is natively "SMP safe", no serialization required).
  *   UP  : other atomics disable IRQ, so no way a difft ctxt atomic_xchg()
  *         could clobber them. atomic_xchg() itself would be 1 insn, so it