nfp: correct cleanup related to DCB resources

This patch corrects two oversights relating to releasing resources
and DCB initialisation.

1. If mapping of the dcbcfg_tbl area fails: an error should be
   propagated, allowing partial initialisation (probe) to be unwound.

2. Conversely, if where dcbcfg_tbl is successfully mapped: it should
   be unmapped in nfp_nic_dcb_clean() which is called via various error
   cleanup paths, and shutdown or removal of the PCIE device.

Fixes: 9b7fe80 ("nfp: add DCB IEEE support")
Signed-off-by: Huayu Chen <huayu.chen@corigine.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20230131163033.981937-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Huayu-Chen

drivers/net/ethernet/netronome/nfp/nic/main.c

@@ -32,9 +32,12 @@ static void nfp_nic_sriov_disable(struct nfp_app *app)
 
 static int nfp_nic_vnic_init(struct nfp_app *app, struct nfp_net *nn)
 {
-	nfp_nic_dcb_init(nn);
+	return nfp_nic_dcb_init(nn);
+}
 
-	return 0;
+static void nfp_nic_vnic_clean(struct nfp_app *app, struct nfp_net *nn)
+{
+	nfp_nic_dcb_clean(nn);
 }
 
 static int nfp_nic_vnic_alloc(struct nfp_app *app, struct nfp_net *nn,
@@ -72,4 +75,5 @@ const struct nfp_app_type app_nic = {
 	.sriov_disable	= nfp_nic_sriov_disable,
 
 	.vnic_init      = nfp_nic_vnic_init,
+	.vnic_clean     = nfp_nic_vnic_clean,
 };

drivers/net/ethernet/netronome/nfp/nic/main.h

@@ -33,7 +33,7 @@ struct nfp_dcb {
 int nfp_nic_dcb_init(struct nfp_net *nn);
 void nfp_nic_dcb_clean(struct nfp_net *nn);
 #else
-static inline int nfp_nic_dcb_init(struct nfp_net *nn) {return 0; }
+static inline int nfp_nic_dcb_init(struct nfp_net *nn) { return 0; }
 static inline void nfp_nic_dcb_clean(struct nfp_net *nn) {}
 #endif