Really support Ultra-2 chips. Symbios redefined a register that

Really support Ultra-2 chips. Symbios redefined a register that
was available to the programmer to hold chip state information:

Use the SDID register instead of CTEST3. This change actually
simplifies the SCRIPTS code, but I'm not absolutely sure, that
it is OK for all variants of NCR chips around and all device
combinations. I have had this code running on several systems
with 53c810, 875 and 895 controllers for several months.

Suggested by:	Gerard Roudier <groudier@club-internet.fr>