ionic: clean interrupt before enabling queue to avoid credit race

Clear the interrupt credits before enabling the queue rather
than after to be sure that the enabled queue starts at 0 and
that we don't wipe away possible credits after enabling the
queue.

Fixes: 0f3154e6 ("ionic: Add Tx and Rx handling")
Signed-off-by: Neel Patel <neel.patel@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>