Moving Vela to use TOSA v0.80.0 specification

 * Using serialization_lib main branch to update statically copied
   files sha 5f920211ac23393a7b98a0d358bfbfc3232d5c8f (v0.80.0)
 * All files within the ethosu/vela/tosa are copied from that revision
 * Note: hope to move to serialization_lib as a pip module in future

 * Modified the ethosu/vela/{tosa_mapping,tosa_reader}.py to use
   v0.80.0 TOSA FlatBuffers implementation
 * These are the additional changes made to support this new version,
   with changes in the format of the FlatBuffers file and where various
   values are stored. Either changing from input to attribute, or
   moving to different attributes.

Signed-off-by: Rob Elliott <robert.elliott@arm.com>
Change-Id: I5e1fcc2a9964148619be3477adf1e88e84cbae2d