staging: octeon: ethernet-mdio.c Fix line over 80 characters.

Fix checkpatch.pl issue with
line over 80 characters in ethernet-mdio.c

Signed-off-by: Aybuke Ozdemir <aybuke.147@gmail.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>