Don't populate the arrays ReadCacheStatus, WriteCacheStatus and
SenseErrors on the stack but instead make them static const. Makes
the object code smaller by 47 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
 160974	  34628	    832	 196434	  2ff52	drivers/block/DAC960.o

After:
   text	   data	    bss	    dec	    hex	filename
 160671	  34884	    832	 196387	  2ff23	drivers/block/DAC960.o

(gcc version 8.2.0 x86_64)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>