arm64: dts: juno: Enable coresight tmc scatter gather in ETR

We do not enable scatter-gather mode in the TMC-ETR by default
to prevent malfunctioning of systems where the ETR may not be
properly connected to the memory subsystem to allow for simultaneous
READ/WRITE transactions when used in SG mode. Instead we whitelist
the platforms where we know that it is safe to use the mode.

All revisions of Juno have a proper ETR connection and hence
white list them.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pierlisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

arch/arm64/boot/dts/arm/juno-base.dtsi

@@ -193,6 +193,7 @@
 		clocks = <&soc_smc50mhz>;
 		clock-names = "apb_pclk";
 		power-domains = <&scpi_devpd 0>;
+		arm,scatter-gather;
 		in-ports {
 			port {
 				etr_in_port: endpoint {