drm/amd/display: fix a coding error causing set throttled vcp size skipped for dpia

[why]
There is a recent refactor that contains a typo to cause set throttled
vcp size skipped for dpia link. The change is to fix this typo so it won't cause
black screen
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -926,7 +926,7 @@ static bool can_use_dpia_link_hwss(const struct dc_link *link,
 }
 
 static const struct link_hwss dpia_link_hwss = {
-	.set_throttled_vcp_size = set_dummy_throttled_vcp_size,
+	.set_throttled_vcp_size = set_dio_throttled_vcp_size,
 };
 
 /*********************** below goes to link_hwss ******************************/