drm/i915/selftests: Add helper function measure_power

move the power measurement and the triangle filter
to a different function. No functional changes.
Signed-off-by: NRiana Tauro <riana.tauro@intel.com>
Reviewed-by: NVinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: NAnshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220923110043.789178-3-riana.tauro@intel.com

drivers/gpu/drm/i915/gt/selftest_rps.c

@@ -1107,21 +1107,27 @@ static u64 __measure_power(int duration_ms)
 	return div64_u64(1000 * 1000 * dE, dt);
 }
 
-static u64 measure_power_at(struct intel_rps *rps, int *freq)
+static u64 measure_power(struct intel_rps *rps, int *freq)
 {
 	u64 x[5];
 	int i;
 
-	*freq = rps_set_check(rps, *freq);
 	for (i = 0; i < 5; i++)
 		x[i] = __measure_power(5);
-	*freq = (*freq + read_cagf(rps)) / 2;
+
+	*freq = (*freq + intel_rps_read_actual_frequency(rps)) / 2;
 
 	/* A simple triangle filter for better result stability */
 	sort(x, 5, sizeof(*x), cmp_u64, NULL);
 	return div_u64(x[1] + 2 * x[2] + x[3], 4);
 }
 
+static u64 measure_power_at(struct intel_rps *rps, int *freq)
+{
+	*freq = rps_set_check(rps, *freq);
+	return measure_power(rps, freq);
+}
+
 int live_rps_power(void *arg)
 {
 	struct intel_gt *gt = arg;