drm/amd/display: make enc32_stream_encoder_dvi_set_stream_attribute static

This symbol is not used outside of dcn32_dio_stream_encoder.c, so marks
it static.

drivers/gpu/drm/amd/amdgpu/../display/dc/dcn32/dcn32_dio_stream_encoder.c:63:6: warning: no previous prototype for ‘enc32_stream_encoder_dvi_set_stream_attribute’.

Link:https://bugzilla.openanolis.cn/show_bug.cgi?id=2119Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dio_stream_encoder.c

@@ -60,7 +60,7 @@ static void enc32_dp_set_odm_combine(
 }
 
 /* setup stream encoder in dvi mode */
-void enc32_stream_encoder_dvi_set_stream_attribute(
+static void enc32_stream_encoder_dvi_set_stream_attribute(
 	struct stream_encoder *enc,
 	struct dc_crtc_timing *crtc_timing,
 	bool is_dual_link)