drm/amd/display: fix a divided-by-zero error

[Why & How]

timing.dsc_cfg.num_slices_v can be zero and it is necessary to check
before using it.

This fixes the error "divide error: 0000 [#1] PREEMPT SMP NOPTI".

Reviewed-by: Aurabindo Pillai <[email protected]>
Acked-by: Qingqing Zhuo <[email protected]>
Signed-off-by: Alex Hung <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Cc: [email protected]

Author: Alex Hung

drivers/gpu/drm/amd/display/modules/power/power_helpers.c

@@ -934,6 +934,10 @@ bool psr_su_set_dsc_slice_height(struct dc *dc, struct dc_link *link,
 
 	pic_height = stream->timing.v_addressable +
 		stream->timing.v_border_top + stream->timing.v_border_bottom;
+
+	if (stream->timing.dsc_cfg.num_slices_v == 0)
+		return false;
+
 	slice_height = pic_height / stream->timing.dsc_cfg.num_slices_v;
 	config->dsc_slice_height = slice_height;