A separate field isn't strictly required. The core field could be
re-used for thread IDs as a single field was used previously.

But separating them will avoid confusion and catch potential errors
where core IDs are read as thread IDs and vice versa.

Also remove the placeholder id field which is now no longer used.
Signed-off-by: NJames Clark <james.clark@arm.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: NJohn Garry <john.garry@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20201126141328.6509-13-james.clark@arm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>