staging: octeon: fix restricted __be16 degrades to integer

Add cast to fix the following sparse warning:
warning: restricted __be16 degrades to integer

Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Link: https://lore.kernel.org/r/20191015084731.8514-1-wambui.karugax@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>