perf cs-etm: Create ETE decoder

If the magic number indicates ETE instantiate a OCSD_BUILTIN_DCD_ETE
decoder instead of OCSD_BUILTIN_DCD_ETMV4I. ETE is the new trace feature
for Armv9.

Testing performed
=================

* Old files with v0 and v1 headers for ETMv4 still open correctly
* New files with new magic number open on new versions of perf
* New files with new magic number fail to open on old versions of perf
* Decoding with the ETE decoder results in the same output as the ETMv4
  decoder as long as there are no new ETE packet types

Signed-off-by: James Clark <james.clark@arm.com>