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/tflite_reader.py b/ethosu/vela/tflite_reader.py
index 93b97f6..df52478 100644
--- a/ethosu/vela/tflite_reader.py
+++ b/ethosu/vela/tflite_reader.py
@@ -121,7 +121,7 @@
         if dtype == DataType.uint8:
             tens.quantization.quant_min = 0
             tens.quantization.quant_max = (1 << dtype.bits) - 1
-        elif dtype in set((DataType.int8, DataType.int16, DataType.int32, DataType.int64)):
+        elif dtype in (DataType.int8, DataType.int16, DataType.int32, DataType.int64):
             tens.quantization.quant_min = -(1 << (dtype.bits - 1))
             tens.quantization.quant_max = (1 << (dtype.bits - 1)) - 1