ethtool: fix incorrect kernel-doc style comment in ethtool.h

Building documentation produced the following warning:

  WARNING: ./include/linux/ethtool.h:495 This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * IEEE 802.3ck/df defines 16 bins for FEC histogram plus one more for

This comment was not intended to be parsed as kernel-doc, so replace
the '/**' with '/*' to silence the warning and align with normal
comment style in header files.

No functional changes.

Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
Link: https://patch.msgid.link/20251110182545.2112596-1-kriish.sharma2006@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: KRIISHSHARMA

include/linux/ethtool.h

@@ -492,7 +492,7 @@ struct ethtool_pause_stats {
 };
 
 #define ETHTOOL_MAX_LANES	8
-/**
+/*
  * IEEE 802.3ck/df defines 16 bins for FEC histogram plus one more for
  * the end-of-list marker, total 17 items
  */