rapidio: remove excess kernel-doc notation

Remove excess kernel-doc notation from rio header and driver:

Warning(include/linux/rio_drv.h:399): Excess function parameter or struct member 'buffer' description in 'rio_get_inb_message'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>