scsi: scsi_debug: Make read-only arrays static const

Don't populate the read-only arrays on the stack at run time, instead
make them static const. Also reduces overall size.

before:
   text	   data	    bss	    dec	    hex	filename
 367439	  89582	   5952	 462973	  7107d	drivers/scsi/scsi_debug.o

after:
   text	   data	    bss	    dec	    hex	filename
 365847	  90702	   5952	 462501	  70ea5	drivers/scsi/scsi_debug.o

(gcc 14.2.0, x86-64)

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20250729064930.1659007-1-colin.i.king@gmail.com


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>