powercap: DTPM: Check for Energy Model type

The Energy Model power values might be artificial. In such case
it's safe to bail out during the registration, since the PowerCap
framework supports only micro-Watts.
Signed-off-by: NLukasz Luba <lukasz.luba@arm.com>
Reviewed-by: NIonela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/powercap/dtpm_cpu.c

@@ -211,7 +211,7 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
 		return 0;
 
 	pd = em_cpu_get(cpu);
-	if (!pd)
+	if (!pd || em_is_artificial(pd))
 		return -EINVAL;
 
 	dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);