bnxt_en: Improve the IRQ disable sequence during shutdown.

bnxt_en: Improve the IRQ disable sequence during shutdown.

Orabug: 25645429

The IRQ is disabled by writing to the completion ring doorbell.  This
should be done before the hardware completion ring is freed for correctness.
The current code disables IRQs after all the completion rings are freed.

Fix it by calling bnxt_disable_int_sync() before freeing the completion
rings.  Rearrange the code to avoid forward declaration.

Signed-off-by: Michael Chan <michael.chan@broadocm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 9d8bc09766f1a229b2d204c713a1cfc6c7fa1bb1)
Signed-off-by: Brian Maly <brian.maly@oracle.com>