perf/smmuv3: Don't trample existing events with global filter

perf/smmuv3: Don't trample existing events with global filter

With global filtering, we only allow an event to be scheduled if its
filter settings exactly match those of any existing events, therefore
it is pointless to reapply the filter in that case. Much worse, though,
is that in doing that we trample the event type of counter 0 if it's
already active, and never touch the appropriate PMEVTYPERn so the new
event is likely not counting the right thing either. Don't do that.

CC: stable@vger.kernel.org
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/32c80c0e46237f49ad8da0c9f8864e13c4a803aa.1623153312.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>