sfc: Update and improve kernel-doc for efx_mcdi_state & efx_mcdi_iface

#define EFX_MCDI_H

/**

 * enum efx_mcdi_state

 * enum efx_mcdi_state - MCDI request handling state

 * @MCDI_STATE_QUIESCENT: No pending MCDI requests. If the caller holds the

 *	mcdi_lock then they are able to move to MCDI_STATE_RUNNING

 *	mcdi @iface_lock then they are able to move to %MCDI_STATE_RUNNING

 * @MCDI_STATE_RUNNING: There is an MCDI request pending. Only the thread that

 *	moved into this state is allowed to move out of it.

 * @MCDI_STATE_COMPLETED: An MCDI request has completed, but the owning thread

 *	has not yet consumed the result. For all other threads, equivalent to

 *	MCDI_STATE_RUNNING.

 *	%MCDI_STATE_RUNNING.

 */

enum efx_mcdi_state {

	MCDI_STATE_QUIESCENT,

};

/**

 * struct efx_mcdi_iface

 * @state: Interface state. Waited for by mcdi_wq.

 * @wq: Wait queue for threads waiting for state != STATE_RUNNING

 * @iface_lock: Protects @credits, @seqno, @resprc, @resplen

 * struct efx_mcdi_iface - MCDI protocol context

 * @state: Request handling state. Waited for by @wq.

 * @mode: Poll for mcdi completion, or wait for an mcdi_event.

 *	Serialised by @lock

 * @wq: Wait queue for threads waiting for @state != %MCDI_STATE_RUNNING

 * @iface_lock: Serialises access to all the following fields

 * @seqno: The next sequence number to use for mcdi requests.

 *	Serialised by @lock

 * @credits: Number of spurious MCDI completion events allowed before we

 *	trigger a fatal error. Protected by @lock

 *     trigger a fatal error

 * @resprc: Response error/success code (Linux numbering)

 * @resp_hdr_len: Response header length

 * @resp_data_len: Response data (SDU or error) length

 */

struct efx_mcdi_iface {

	atomic_t state;

	enum efx_mcdi_mode mode;

	wait_queue_head_t wq;

	spinlock_t iface_lock;

	enum efx_mcdi_mode mode;

	unsigned int credits;

	unsigned int seqno;

	int resprc;