drm/amd/display: Simplify bool comparison

Fix the following coccicheck warning:
./drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c:1228:9-20:
WARNING: Comparison to bool
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <abaci-bugfix@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c

@@ -1219,13 +1219,13 @@ static bool CalculatePrefetchSchedule(
 			dml_print("DML: prefetch_bw_equ: %f\n", prefetch_bw_equ);
 
 			if (prefetch_bw_equ > 0) {
-				if (GPUVMEnable == true) {
+				if (GPUVMEnable) {
 					Tvm_equ = dml_max3(*Tno_bw + PDEAndMetaPTEBytesFrame * HostVMInefficiencyFactor / prefetch_bw_equ, Tvm_trips, LineTime / 4);
 				} else {
 					Tvm_equ = LineTime / 4;
 				}
 
-				if ((GPUVMEnable == true || myPipe->DCCEnable == true)) {
+				if ((GPUVMEnable || myPipe->DCCEnable)) {
 					Tr0_equ = dml_max4(
 							(MetaRowByte + PixelPTEBytesPerRow * HostVMInefficiencyFactor) / prefetch_bw_equ,
 							Tr0_trips,