sfc: Limit scope of a Falcon A1 IRQ workaround

We unconditionally acknowledge legacy interrupts just before disabling
them.  This workaround is needed on Falcon A1 but probably not on
later chips where the legacy interrupt mechanism is different.  It was
also originally done after the IRQ handler was removed, not before.
Restore the original behaviour for Falcon A1 only by doing this
acknowledgement in the efx_nic_type::fini operation.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/falcon.c b/drivers/net/ethernet/sfc/falcon.c
index f8de382..4492129 100644
--- a/drivers/net/ethernet/sfc/falcon.c
+++ b/drivers/net/ethernet/sfc/falcon.c
@@ -336,7 +336,7 @@
  *
  * NB most hardware supports MSI interrupts
  */
-inline void falcon_irq_ack_a1(struct efx_nic *efx)
+static inline void falcon_irq_ack_a1(struct efx_nic *efx)
 {
 	efx_dword_t reg;
 
@@ -2343,7 +2343,7 @@
 	.remove = falcon_remove_nic,
 	.init = falcon_init_nic,
 	.dimension_resources = falcon_dimension_resources,
-	.fini = efx_port_dummy_op_void,
+	.fini = falcon_irq_ack_a1,
 	.monitor = falcon_monitor,
 	.map_reset_reason = falcon_map_reset_reason,
 	.map_reset_flags = falcon_map_reset_flags,