feat: indent log on property applying and layer assignment

Indent when applying properties and assigning the layers. The log is better to
read this way. Example:

Apply on output 0x55c447db2b50.
Layers on CRTC 62:
  Layer 0x55c447db2a40:
    FB_ID = 108
    zpos = 0
    alpha = 65535
    SRC_X = 0
    SRC_Y = 0
    SRC_W = 3840
    SRC_H = 2160
    CRTC_X = 0
    CRTC_Y = 0
    CRTC_W = 3840
    CRTC_H = 2160
Disabling planes: 55 52 49 46 43 40 71 69 67 65 63 61 58
Performing allocation for plane 55 (1/13)
  Layer 0x55c447db2a40 -> plane 55: applying properties...
  Layer 0x55c447db2a40 -> plane 55: incompatible properties
Performing allocation for plane 61 (12/13)
  Layer 0x55c447db2a40 -> plane 61: applying properties...
  Layer 0x55c447db2a40 -> plane 61: incompatible properties
Performing allocation for plane 58 (13/13)
  Layer 0x55c447db2a40 -> plane 58: applying properties...
  Layer 0x55c447db2a40 -> plane 58: success
Found a better allocation with score=1
Found plane allocation for output 0x55c447db2b50 with score=1
Assigning layers to planes:
  Layer 0x55c447db2a40 -> plane 58

alloc.c

@@ -406,15 +406,15 @@ bool output_choose_layers(struct liftoff_output *output,
 		}
 
 		/* Try to use this layer for the current plane */
-		liftoff_log(LIFTOFF_DEBUG, "Layer %p -> plane %"PRIu32": "
+		liftoff_log(LIFTOFF_DEBUG, "  Layer %p -> plane %"PRIu32": "
 			    "applying properties...",
 			    (void *)layer, plane->id);
 		if (!plane_apply(plane, layer, result->req, &compatible)) {
 			return false;
 		}
 		if (!compatible) {
 			liftoff_log(LIFTOFF_DEBUG,
-				    "Layer %p -> plane %"PRIu32": "
+					"  Layer %p -> plane %"PRIu32": "
 				    "incompatible properties",
 				    (void *)layer, plane->id);
 			continue;
@@ -425,7 +425,7 @@ bool output_choose_layers(struct liftoff_output *output,
 		}
 		if (compatible) {
 			liftoff_log(LIFTOFF_DEBUG,
-				    "Layer %p -> plane %"PRIu32": success",
+					"  Layer %p -> plane %"PRIu32": success",
 				    (void *)layer, plane->id);
 			/* Continue with the next plane */
 			plane_step_init_next(&next_step, step, layer);
@@ -667,6 +667,7 @@ bool liftoff_output_apply(struct liftoff_output *output, drmModeAtomicReq *req)
 		    "score=%d", (void *)output, result.best_score);
 
 	/* Apply the best allocation */
+	liftoff_log(LIFTOFF_DEBUG, "Assigning layers to planes:");
 	i = 0;
 	liftoff_list_for_each(plane, &device->planes, link) {
 		layer = result.best[i];
@@ -675,8 +676,7 @@ bool liftoff_output_apply(struct liftoff_output *output, drmModeAtomicReq *req)
 			continue;
 		}
 
-		liftoff_log(LIFTOFF_DEBUG,
-			    "Assigning layer %p to plane %"PRIu32,
+		liftoff_log(LIFTOFF_DEBUG, "  Layer %p -> plane %"PRIu32,
 			    (void *)layer, plane->id);
 
 		assert(plane->layer == NULL);
@@ -685,6 +685,8 @@ bool liftoff_output_apply(struct liftoff_output *output, drmModeAtomicReq *req)
 		layer->plane = plane;
 	}
 
+	liftoff_log(LIFTOFF_DEBUG, "");
+
 	if (!apply_current(device, req)) {
 		return false;
 	}