init routine

The Sram init(D2osdi) routine initializes memory for the RAM disk, sets up some basic information, and registers the driver with the SCSI subsystem. The logic is:

1. Call memget(D3oddi) to allocate memory for the RAM disk, then zero it out with bzero(D3oddi).

2. Set driver-specific pointers to define the allocated memory.

3. Populate the xx_info structure with information about this host adapter.

4. Populate the regit structure, the call Sharegister(D3osdi) with a pointer to the regit structure to register the driver with the SCSI subsystem.