UPSTREAM: perf/arm-cmn: Refactor node ID handling

Add a bit more abstraction for the places where we decompose node IDs.
This will help keep things nice and manageable when we come to add yet
more variables which affect the node ID format. Also use the opportunity
to move the rest of the low-level node management helpers back up to the
logical place they were meant to be - how they ended up buried right in
the middle of the event-related definitions is somewhat of a mystery...

Bug: 247832918
Change-Id: Ibf87685678e1c5fda40ddbb8d1fd5430d24f0914
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/a2242a8c3c96056c13a04ae87bf2047e5e64d2d9.1638530442.git.robin.murphy@arm.com


Signed-off-by: Will Deacon <will@kernel.org>
(cherry picked from commit 5f167eab)
Signed-off-by: Robin Peng <robinpeng@google.com>