drm/amd/display: Deallocate DML memory if allocation fails

[Why]
When DC state create DML memory allocation fails, memory is not
deallocated subsequently, resulting in uninitialized structure
that is not NULL.

[How]
Deallocate memory if DML memory allocation fails.

Reviewed-by: Joshua Aberback <[e-mail]>
Signed-off-by: Jerry Zuo <[e-mail]>
Signed-off-by: Chris Park <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/core/dc_state.c

···
 #ifdef CONFIG_DRM_AMD_DC_FP
 	if (dc->debug.using_dml2) {
 		dml2_opt->use_clock_dc_limits = false;
-		dml2_create(dc, dml2_opt, &state->bw_ctx.dml2);
+		if (!dml2_create(dc, dml2_opt, &state->bw_ctx.dml2)) {
+			dc_state_release(state);
+			return NULL;
+		}
 
 		dml2_opt->use_clock_dc_limits = true;
-		dml2_create(dc, dml2_opt, &state->bw_ctx.dml2_dc_power_source);
+		if (!dml2_create(dc, dml2_opt, &state->bw_ctx.dml2_dc_power_source)) {
+			dc_state_release(state);
+			return NULL;
+		}
 	}
 #endif