scsi: tcmu: remove useless code and clean up the code style.

Since the TCMU_RING_SIZE macro is not using here will discard it and at the
same time clean up the code style.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Acked-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_user.c

@@ -83,14 +83,10 @@
 #define DATA_BLOCK_SIZE PAGE_SIZE
 #define DATA_BLOCK_SHIFT PAGE_SHIFT
 #define DATA_BLOCK_BITS_DEF (256 * 1024)
-#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
 
 #define TCMU_MBS_TO_BLOCKS(_mbs) (_mbs << (20 - DATA_BLOCK_SHIFT))
 #define TCMU_BLOCKS_TO_MBS(_blocks) (_blocks >> (20 - DATA_BLOCK_SHIFT))
 
-/* The total size of the ring is 8M + 256K * PAGE_SIZE */
-#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
-
 /*
  * Default number of global data blocks(512K * PAGE_SIZE)
  * when the unmap thread will be started.