xen: xenbus_dev.h: delete incorrect file name

It is better/preferred not to include file names in source files
because (a) they are not needed and (b) they can be incorrect,
so just delete this incorrect file name.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: xen-devel@lists.xenproject.org
Link: https://lore.kernel.org/r/20220130191705.24971-1-rdunlap@infradead.orgSigned-off-by: Juergen Gross <jgross@suse.com>

include/xen/xenbus_dev.h

 /******************************************************************************
- * evtchn.h
- *
  * Interface to /dev/xen/xenbus_backend.
  *
  * Copyright (c) 2011 Bastian Blank <waldi@debian.org>