staging: vt6655: desc.h remove dead strctures

Remove these unsed structures.
typedef struct tagSTxSyncDesc
typedef struct tagSRrvTime_atim
typedef struct tagSTxBufHead
typedef struct tagSBEACONCtl
typedef struct tagSSecretKey
typedef struct tagSKeyEntry

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>