drm/amd/display: remove conversion to bool in dcn20_mpc.c

The '==' expression itself is bool, no need to convert it to bool again.
This fixes the following coccicheck warning:

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c:455:70-75: WARNING:
conversion to bool not needed here
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_mpc.c

@@ -452,7 +452,7 @@ void mpc2_set_output_gamma(
 		next_mode = LUT_RAM_A;
 
 	mpc20_power_on_ogam_lut(mpc, mpcc_id, true);
-	mpc20_configure_ogam_lut(mpc, mpcc_id, next_mode == LUT_RAM_A ? true:false);
+	mpc20_configure_ogam_lut(mpc, mpcc_id, next_mode == LUT_RAM_A);
 
 	if (next_mode == LUT_RAM_A)
 		mpc2_program_luta(mpc, mpcc_id, params);