aco: fix C++11/C++14 compilation

static_assert without a message is only available since C++17.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Fixes: d1f992f3c2d ('aco: rework barriers and replace can_reorder')
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3374
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6216>
diff --git a/src/amd/compiler/aco_ir.h b/src/amd/compiler/aco_ir.h
index 9dda1ff..1d6220e 100644
--- a/src/amd/compiler/aco_ir.h
+++ b/src/amd/compiler/aco_ir.h
@@ -174,7 +174,7 @@
       return (!storage || (semantics & semantic_can_reorder)) && !(semantics & semantic_volatile);
    }
 };
-static_assert(sizeof(memory_sync_info) == 3);
+static_assert(sizeof(memory_sync_info) == 3, "Unexpected padding");
 
 enum fp_round {
    fp_round_ne = 0,