drm/amd/display: remove duplicate include header

link_hwss.h is included more than once in link_dpms.c .
Signed-off-by: Ye Xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/link/link_dpms.c

@@ -51,7 +51,6 @@
 #include "link_enc_cfg.h"
 #include "resource.h"
 #include "dsc.h"
-#include "link_hwss.h"
 #include "dccg.h"
 #include "clk_mgr.h"
 #include "atomfirmware.h"