MLBEDSW-4838 Added basic TOSA support.

Added basic TOSA support, enabling Vela to
read and compile  a .tosa file corresponding to
CONV2D + Rescale + Clamp, and writing it to an
optimized .tflite file.

The optimized .tflite file, will in this case, hold
a commandstream where the Rescale and Clamp has been
fused into the CONV2D.

The optimized tflite file is not output from Vela.

  -Added support to read .tosa file into Vela
    internal structure.
      - Added tosa_reader.py, tosa_mapper.py and
        helper files stored under tosa/
      - Support for this limited to ~10 ops

    -Added reader_util.py for functions common
    for TOSA and TFLite

    -Added tosa_graph_optimiser.py
      -Added support to fuse Rescale into convolution
      -Modified handling for padding

    -Added support to fuse Clamp to previous op

    -Added graph_optimiser_util.py
      -Moved functions common for TOSA/TFLite graph
       optimization to this file.

    -Renamed graph_optimiser.py to tflite_graph_optmiser.py

    -Added separate tosa_supported_operators.py

    -Added supported_operator_util.py
       -For functions in common for TOSA/TFLite

Signed-off-by: Patrik Gustavsson <patrik.gustavsson@arm.com>
Change-Id: Ic3c540504ec8c5eb4771397fdc6882050ecf33ab
diff --git a/ethosu/vela/tosa/Attribute.py b/ethosu/vela/tosa/Attribute.py
new file mode 100644
index 0000000..8a2ccae
--- /dev/null
+++ b/ethosu/vela/tosa/Attribute.py
@@ -0,0 +1,22 @@
+# automatically generated by the FlatBuffers compiler, do not modify
+
+# namespace: tosa
+
+class Attribute(object):
+    NONE = 0
+    Pool2dAttribute = 1
+    Conv2dAttribute = 2
+    TransposeConv2dAttribute = 3
+    ReluNAttribute = 4
+    AxisAttribute = 5
+    ReshapeAttribute = 6
+    SliceAttribute = 7
+    TileAttribute = 8
+    ResizeAttribute = 9
+    ClampAttribute = 10
+    RescaleAttribute = 11
+    MulAttribute = 12
+    ArithmeticRightShiftAttribute = 13
+    CondIfAttribute = 14
+    WhileLoopAttribute = 15
+