arch,hexagon: Convert smp_mb__*()

Hexagon uses asm-gemeric/barrier.h and its smp_mb() is barrier().
Therefore we can use the default implementation that uses smp_mb().
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-87irqrrbgizeojjfdqhypud3@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-hexagon@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/hexagon/include/asm/atomic.h

@@ -24,6 +24,7 @@
 
 #include <linux/types.h>
 #include <asm/cmpxchg.h>
+#include <asm/barrier.h>
 
 #define ATOMIC_INIT(i)		{ (i) }
 
@@ -176,9 +177,4 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u)
 #define atomic_inc_return(v) (atomic_add_return(1, v))
 #define atomic_dec_return(v) (atomic_sub_return(1, v))
 
-#define smp_mb__before_atomic_dec()	barrier()
-#define smp_mb__after_atomic_dec()	barrier()
-#define smp_mb__before_atomic_inc()	barrier()
-#define smp_mb__after_atomic_inc()	barrier()
-
 #endif

arch/hexagon/include/asm/bitops.h

@@ -25,12 +25,10 @@
 #include <linux/compiler.h>
 #include <asm/byteorder.h>
 #include <asm/atomic.h>
+#include <asm/barrier.h>
 
 #ifdef __KERNEL__
 
-#define smp_mb__before_clear_bit()	barrier()
-#define smp_mb__after_clear_bit()	barrier()
-
 /*
  * The offset calculations for these are based on BITS_PER_LONG == 32
  * (i.e. I get to shift by #5-2 (32 bits per long, 4 bytes per access),