rsi: remove kernel-doc comment marker

Change an errant kernel-doc comment marker (/**) to a regular
comment to prevent a kernel-doc warning.

rsi_91x.h:3: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Copyright (c) 2017 Redpine Signals Inc.

Fixes: 4c10d56a ("rsi: add header file rsi_91x")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Cc: Siva Rebbagondla <siva.rebbagondla@redpinesignals.com>
Acked-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230714045127.18752-10-rdunlap@infradead.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/rsi_91x.h

-/**
+/*
  * Copyright (c) 2017 Redpine Signals Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any