drm/amd/display: Fix unsigned comparison with less than zero

The return value from the call to dml21_find_dc_pipes_for_plane() is int.
However, the return value is being assigned to an unsigned int variable
'num_pipes', the condition if(num_pipes <= 0) is not rigorous enough,
so making 'num_pipes' an int.

./drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c:318:6-15: WARNING: Unsigned expression compared with zero: num_pipes <= 0.
./drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c:360:6-15: WARNING: Unsigned expression compared with zero: num_pipes <= 0.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9454Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dml2/dml21/dml21_wrapper.c

@@ -285,7 +285,8 @@ bool dml21_validate(const struct dc *in_dc, struct dc_state *context, struct dml
 
 void dml21_prepare_mcache_programming(struct dc *in_dc, struct dc_state *context, struct dml2_context *dml_ctx)
 {
-	unsigned int num_pipes, dml_prog_idx, dml_phantom_prog_idx, dc_pipe_index;
+	unsigned int dml_prog_idx, dml_phantom_prog_idx, dc_pipe_index;
+	int num_pipes;
 	struct pipe_ctx *dc_main_pipes[__DML2_WRAPPER_MAX_STREAMS_PLANES__];
 	struct pipe_ctx *dc_phantom_pipes[__DML2_WRAPPER_MAX_STREAMS_PLANES__] = {0};
 
@@ -319,10 +320,8 @@ void dml21_prepare_mcache_programming(struct dc *in_dc, struct dc_state *context
 		}
 
 		num_pipes = dml21_find_dc_pipes_for_plane(in_dc, context, dml_ctx, dc_main_pipes, dc_phantom_pipes, dml_prog_idx);
-
-		if (num_pipes <= 0 ||
-				dc_main_pipes[0]->stream == NULL ||
-				dc_main_pipes[0]->plane_state == NULL)
+		if (num_pipes <= 0 || dc_main_pipes[0]->stream == NULL ||
+		    dc_main_pipes[0]->plane_state == NULL)
 			continue;
 
 		/* get config for each pipe */
@@ -361,10 +360,8 @@ void dml21_prepare_mcache_programming(struct dc *in_dc, struct dc_state *context
 		pln_prog = &dml_ctx->v21.mode_programming.programming->plane_programming[dml_prog_idx];
 
 		num_pipes = dml21_find_dc_pipes_for_plane(in_dc, context, dml_ctx, dc_main_pipes, dc_phantom_pipes, dml_prog_idx);
-
-		if (num_pipes <= 0 ||
-				dc_main_pipes[0]->stream == NULL ||
-				dc_main_pipes[0]->plane_state == NULL)
+		if (num_pipes <= 0 || dc_main_pipes[0]->stream == NULL ||
+		    dc_main_pipes[0]->plane_state == NULL)
 			continue;
 
 		/* get config for each pipe */