simpleperf: Support decoding unformatted ETM traces.

Some devices, like TRBE, produce unformatted traces. These cannot be
decoded by the formatted frame decoder, the underlying packet decoders
have to be used. This change recognizes unformatted traces and uses
the correct decoder to handle them.

Test: simpleperf_unit_test

Change-Id: I7e1a0c81a34c07a6f9e8cf6bceca6bf2592be0d9
8 files changed