drm/xe: Fix bo leak in intel_fb_bo_framebuffer_init

Add a unreference bo in the error path, to prevent leaking a bo ref.

Return 0 on success to clarify the success path.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 44e69495 ("drm/xe/display: Implement display support")
Cc: <stable@vger.kernel.org> # v6.8+
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240404090302.68422-1-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/xe/display/intel_fb_bo.c

@@ -31,7 +31,7 @@ int intel_fb_bo_framebuffer_init(struct intel_framebuffer *intel_fb,
 
 	ret = ttm_bo_reserve(&bo->ttm, true, false, NULL);
 	if (ret)
-		return ret;
+		goto err;
 
 	if (!(bo->flags & XE_BO_FLAG_SCANOUT)) {
 		/*
@@ -42,12 +42,16 @@ int intel_fb_bo_framebuffer_init(struct intel_framebuffer *intel_fb,
 		 */
 		if (XE_IOCTL_DBG(i915, !list_empty(&bo->ttm.base.gpuva.list))) {
 			ttm_bo_unreserve(&bo->ttm);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err;
 		}
 		bo->flags |= XE_BO_FLAG_SCANOUT;
 	}
 	ttm_bo_unreserve(&bo->ttm);
+	return 0;
 
+err:
+	xe_bo_put(bo);
 	return ret;
 }