net: bonding: remove kernel-doc comment marker

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

bonding.h:282: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Returns NULL if the net_device does not belong to any of the bond's slaves

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Link: https://lore.kernel.org/r/20230714045127.18752-2-rdunlap@infradead.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>