drop `struct nvme_get_discovery_args`

[igaw]

should properly also be replaced with something more reasonable.

/**
 * struct nvme_get_discovery_args - Arguments for nvmf_get_discovery_wargs()
 * @c:			Discovery controller
 * @args_size:		Length of the structure
 * @max_retries:	Number of retries in case of failure
 * @result:		The command completion result from CQE dword0
 * @timeout:		Timeout in ms (default: NVME_DEFAULT_IOCTL_TIMEOUT)
 * @lsp:		Log specific field (See enum nvmf_log_discovery_lsp)
 */
struct nvme_get_discovery_args {
	nvme_ctrl_t c;
	int args_size;
	int max_retries;
	__u32 *result;
	__u32 timeout;
	__u8 lsp;
};