drm/amd/display: Uninitialized variables causing 4k60 UCLK to stay at DPM1 and not DPM0

[Why]
SwathSizePerSurfaceY[] and SwathSizePerSurfaceC[] values are uninitialized
 because we are using += instead of = operator.

[How]
Assign values in loop with = operator.

Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Samson Tam <samson.tam@amd.com>
Reviewed-by: Aric Cyr <aric.cyr@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.0.x, 6.1.x

Author: Samson Tam

drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_util_32.c

@@ -6257,12 +6257,12 @@ bool dml32_CalculateDETSwathFillLatencyHiding(unsigned int NumberOfActiveSurface
 	double SwathSizePerSurfaceC[DC__NUM_DPP__MAX];
 	bool NotEnoughDETSwathFillLatencyHiding = false;
 
-	/* calculate sum of single swath size for all pipes in bytes*/
+	/* calculate sum of single swath size for all pipes in bytes */
 	for (k = 0; k < NumberOfActiveSurfaces; k++) {
-		SwathSizePerSurfaceY[k] += SwathHeightY[k] * SwathWidthY[k] * BytePerPixelInDETY[k] * NumOfDPP[k];
+		SwathSizePerSurfaceY[k] = SwathHeightY[k] * SwathWidthY[k] * BytePerPixelInDETY[k] * NumOfDPP[k];
 
 		if (SwathHeightC[k] != 0)
-			SwathSizePerSurfaceC[k] += SwathHeightC[k] * SwathWidthC[k] * BytePerPixelInDETC[k] * NumOfDPP[k];
+			SwathSizePerSurfaceC[k] = SwathHeightC[k] * SwathWidthC[k] * BytePerPixelInDETC[k] * NumOfDPP[k];
 		else
 			SwathSizePerSurfaceC[k] = 0;