perf/arm-cmn: Remove CMN-600 DTC domain special case

The special case for trying to infer the DTC domain for DTC-adjacent
nodes on CMN-600 is fragile and buggy - currently resulting in subtly
messed up DTC counter allocation - and the theoretical benefit it
offers to a tiny minority of use-cases arguably doesn't outweigh the
inconsistency it offers to others anyway. Just get rid of it.

Fixes: ab33c66 ("perf/arm-cmn: Enable per-DTC counter allocation")
Signed-off-by: Robin Murphy <[email protected]>
Link: https://lore.kernel.org/r/67985e39f53b56385d79a4f1264cf7f9cacedb58.1742308248.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <[email protected]>

Author: rmurphy-arm

drivers/perf/arm-cmn.c

@@ -2167,13 +2167,6 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn)
 
 	cmn->xps = arm_cmn_node(cmn, CMN_TYPE_XP);
 
-	if (cmn->part == PART_CMN600 && cmn->num_dtcs > 1) {
-		/* We do at least know that a DTC's XP must be in that DTC's domain */
-		dn = arm_cmn_node(cmn, CMN_TYPE_DTC);
-		for (int i = 0; i < cmn->num_dtcs; i++)
-			arm_cmn_node_to_xp(cmn, dn + i)->dtc = i;
-	}
-
 	for (dn = cmn->dns; dn->type; dn++) {
 		if (dn->type == CMN_TYPE_XP)
 			continue;