nfp: improve app not found message

When driver app matching loaded FW is not found users are faced with:

   nfp: failed to find app with ID 0x%02x

This message does not properly explain that matching driver code is
either not built into the driver or the driver is too old.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_app.c

@@ -124,7 +124,7 @@ struct nfp_app *nfp_app_alloc(struct nfp_pf *pf, enum nfp_app_id id)
 	struct nfp_app *app;
 
 	if (id >= ARRAY_SIZE(apps) || !apps[id]) {
-		nfp_err(pf->cpp, "failed to find app with ID 0x%02hhx\n", id);
+		nfp_err(pf->cpp, "unknown FW app ID 0x%02hhx, driver too old or support for FW not built in\n", id);
 		return ERR_PTR(-EINVAL);
 	}