drm/udl: Replace BUG_ON() with WARN_ON()

BUG_ON() is a tasteless choice as a sanity check for a driver like UDL
that isn't really a core code.  Replace with WARN_ON() and proper
error handling instead.

Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220804075826.27036-5-tiwai@suse.de

drivers/gpu/drm/udl/udl_main.c

@@ -260,7 +260,8 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 	struct udl_device *udl = to_udl(dev);
 	int ret;
 
-	BUG_ON(len > udl->urbs.size);
+	if (WARN_ON(len > udl->urbs.size))
+		return -EINVAL;
 
 	urb->transfer_buffer_length = len; /* set to actual payload len */
 	ret = usb_submit_urb(urb, GFP_ATOMIC);

drivers/gpu/drm/udl/udl_transfer.c

@@ -220,7 +220,8 @@ int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
 	u8 *cmd = *urb_buf_ptr;
 	u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 
-	BUG_ON(!(log_bpp == 1 || log_bpp == 2));
+	if (WARN_ON(!(log_bpp == 1 || log_bpp == 2)))
+		return -EINVAL;
 
 	line_start = (u8 *) (front + byte_offset);
 	next_pixel = line_start;