coresight: hotplug enable/disable etm only for round robin access

Enable and disable ETM during hotplug operations only if ETM is
allowed round-robin access by the funnel when all the ETMs share
the same funnel priority.

For 8960, 8064, etc it is observed that sometimes a core's ETM is
starved by other core ETMs constantly producing data. This works
around an issue seen where setting the prog bit of a core's ETMCR
(i.e. ETMCR[10]) doesn't result in that core's ETMSR[1] getting
set thereby triggering the "timeout while setting prog bit"
warning. Subsequently performaing a manual ETB flush as part of
disabling ETB to retrieve the collected trace data also fails.

Change-Id: I6dd37979058644495d945e80e6a2de4696fc5a20
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>

Documentation/devicetree/bindings/coresight/coresight.txt

@@ -33,6 +33,8 @@ Optional properties:
 - coresight-default-sink : represents the default compile time CoreSight sink
 - qcom,pc-save : program counter save implemented
 - qcom,blk-size : block size for tmc-etr to usb transfers
+- qcom,round-robin : indicates if per core etms are allowed round-robin access
+		     by the funnel
 
 Examples:
 
@@ -106,4 +108,5 @@ Examples:
 		coresight-child-list = <&funnel_kpss>;
 		coresight-child-ports = <0>;
 		qcom,pc-save;
+		qcom,round-robin;
 	};