drm/amd/display: based on flag reset z10 function pointer

[Why & How]
Per hardware requirements, add a flag to control
z10 enable/disable.
Reviewed-by: Sung joon Kim <Sungjoon.Kim@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn31/dcn31_init.c

@@ -149,4 +149,9 @@ void dcn31_hw_sequencer_construct(struct dc *dc)
 		dc->hwss.init_hw = dcn20_fpga_init_hw;
 		dc->hwseq->funcs.init_pipes = NULL;
 	}
+	if (dc->debug.disable_z10) {
+		/*hw not support z10 or sw disable it*/
+		dc->hwss.z10_restore = NULL;
+		dc->hwss.z10_save_init = NULL;
+	}
 }