[V4L2]start channel

/* mm_channel */
typedef enum{
MM_CHANNEL_STATE_NOTUSED = 0, /*not used*/
MM_CHANNEL_STATE_STOPPED, /* stopped */ 
MM_CHANNEL_STATE_ACTIVE, /* active, at least one stream active*/
MM_CHANNEL_STATE_PAUSED, /* paused */
MM_CHANNEL_STATE_MAX
} mm_channel_state_type_t;

/* mm_stream */
typedef enum{
MM_STREAM_STATE_NOTUSED = 0, /* not used */
MM_STREAM_STATE_INITED, /* inited */
MM_STREAM_STATE_ACQUIRED, /* acquired, fd opened */
MM_STREAM_STATE_CFG,  /* fmt&dim configured */
MM_STREAM_STATE_BUFFED, /* buf allocated */
MM_STREAM_STATE_REG, /* buf regged, stream off*/
MM_STREAM_STATE_ACTIVE, /*active */
MM_STREAM_STATE_MAX
}mm_stream_state_type_t;