staging: vchiq_arm: Drop obsolete comment

The BUG_ON has been replaced with WARN_ON. So we can drop the
comment.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20240621131958.98208-3-wahrenst@gmx.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>