drm: Fix drmModeRes leak on error paths

When creating outputs in the drm compositor, if allocating crtcs
fails, then free the drm resources. Also, if the base output list is
empty, free drm resources
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 9796014..67fa500 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -1263,8 +1263,10 @@
 	}
 
 	ec->crtcs = calloc(resources->count_crtcs, sizeof(uint32_t));
-	if (!ec->crtcs)
+	if (!ec->crtcs) {
+		drmModeFreeResources(resources);
 		return -1;
+	}
 
 	ec->num_crtcs = resources->count_crtcs;
 	memcpy(ec->crtcs, resources->crtcs, sizeof(uint32_t) * ec->num_crtcs);
@@ -1295,6 +1297,7 @@
 
 	if (wl_list_empty(&ec->base.output_list)) {
 		fprintf(stderr, "No currently active connector found.\n");
+		drmModeFreeResources(resources);
 		return -1;
 	}