ionic: Fix dim work handling in split interrupt mode

Currently ionic_dim_work() is incorrect when in
split interrupt mode. This is because the interrupt
rate is only being changed for the Rx side even for
dim running on Tx. Fix this by using the qcq from
the container_of macro. Also, introduce some local
variables for a bit of cleanup.

Fixes: a6ff85e0

 ("ionic: remove intr coalesce update from napi")
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231204192234.21017-3-shannon.nelson@amd.com


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