arch,score: Convert smp_mb__*()

arch,score: Convert smp_mb__*()

score fully relies on asm-generic/barrier.h, so it can use its default
implementation.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Lennox Wu <lennox.wu@gmail.com>
Link: http://lkml.kernel.org/n/tip-4mv9svf28lnotjpfuza8urh8@git.kernel.org
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>