MIPS: OCTEON: warn only once if deprecated link status is being used

Avoid flooding kernel log with warnings.

Fixes: 2c0756d3

 ("MIPS: OCTEON: warn if deprecated link status is being used")
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>