Registers and unregisters EnDIVE usage with the driver.

typedef struct _VRAMREGISTERIN {
  ULONG     ulLength;  /*  Length of VRAMREGISTERIN data structure, in bytes.  */
  ULONG     ulHandle;  /*  Handle required when unregistering. */
  ULONG     ulFlags;   /*  Flag indicating type of register. */
} VRAMREGISTERIN;

typedef   VRAMREGISTERIN   * PVRAMREGISTERIN ;