rocker: Simplify the calculation of variables

Fix the following coccicheck warnings:

./drivers/net/ethernet/rocker/rocker_ofdpa.c:926:34-36: WARNING !A || A
&& B is equivalent to !A || B.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Zhong <abaci-bugfix@linux.alibaba.com>
Link: https://lore.kernel.org/r/1611648783-3916-1-git-send-email-abaci-bugfix@linux.alibaba.com


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