dpaa2-eth: Simplify the calculation of variables

Fix the following coccicheck warnings:

./drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c:1651:36-38: WARNING
!A || A && B is equivalent to !A || B.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Acked-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/1612260157-128026-1-git-send-email-jiapeng.chong@linux.alibaba.com


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