bnxt_en: cleanup DIM work on device shutdown

Make sure to cancel any pending work that might update driver coalesce
settings when taking down an interface.

Fixes: 6a8788f25625 ("bnxt_en: add support for software dynamic interrupt moderation")
Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Cc: Michael Chan <michael.chan@broadcom.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -6082,8 +6082,14 @@ static void bnxt_disable_napi(struct bnxt *bp)
 	if (!bp->bnapi)
 		return;
 
-	for (i = 0; i < bp->cp_nr_rings; i++)
+	for (i = 0; i < bp->cp_nr_rings; i++) {
+		struct bnxt_cp_ring_info *cpr = &bp->bnapi[i]->cp_ring;
+
+		if (bp->bnapi[i]->rx_ring)
+			cancel_work_sync(&cpr->dim.work);
+
 		napi_disable(&bp->bnapi[i]->napi);
+	}
 }
 
 static void bnxt_enable_napi(struct bnxt *bp)