bnxt_en: Return proper error code for non-existent NVM variable

For NVM params that are not supported in the current NVM
configuration, return the error as -EOPNOTSUPP.

Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -335,10 +335,17 @@ static int bnxt_hwrm_nvm_req(struct bnxt *bp, u32 param_id, void *msg,
 	} else {
 		rc = hwrm_send_message_silent(bp, msg, msg_len,
 					      HWRM_CMD_TIMEOUT);
-		if (!rc)
+		if (!rc) {
 			bnxt_copy_from_nvm_data(val, data,
 						nvm_param.nvm_num_bits,
 						nvm_param.dl_num_bytes);
+		} else {
+			struct hwrm_err_output *resp = bp->hwrm_cmd_resp_addr;
+
+			if (resp->cmd_err ==
+				NVM_GET_VARIABLE_CMD_ERR_CODE_VAR_NOT_EXIST)
+				rc = -EOPNOTSUPP;
+		}
 	}
 	dma_free_coherent(&bp->pdev->dev, sizeof(*data), data, data_dma_addr);
 	if (rc == -EACCES)