MLBEDSW-2836 Change sets to tuples

Replace conditional checks against sets with tuples.
If not requiring uniqueness, or complex set operations, it is quicker to
use tuples instead.

Signed-off-by: Michael McGeagh <michael.mcgeagh@arm.com>
Change-Id: Ie8732c8d46067244963936c53f0ec81adda50372
diff --git a/ethosu/vela/high_level_command_stream.py b/ethosu/vela/high_level_command_stream.py
index 30e22ff..d057d17 100644
--- a/ethosu/vela/high_level_command_stream.py
+++ b/ethosu/vela/high_level_command_stream.py
@@ -55,8 +55,8 @@
                 new_start_coord[idx] += split_offset[idx]
                 new_end_coord[idx] += split_offset[idx]
 
-        if split_offset is None and npu_block_type in set(
-            (NpuBlockType.ConvolutionMxN, NpuBlockType.VectorProduct, NpuBlockType.ReduceSum)
+        if (split_offset is None) and (
+            npu_block_type in (NpuBlockType.ConvolutionMxN, NpuBlockType.VectorProduct, NpuBlockType.ReduceSum)
         ):
             # these types of operations do a "dot product" or sum over the entire IFM
             new_start_coord[-1] = 0