scsi: target: core: Remove unused macros NONE and ISPRINT

Remove the unuseds macro to fix the following compilation warnings:

drivers/target//target_core_stat.c:34: warning: macro "NONE" is not used [-Wunused-macros]
	#define NONE  "None"

drivers/target//iscsi/iscsi_target_stat.c:36: warning: macro "ISPRINT" is not used [-Wunused-macros]
	#define ISPRINT(a)   ((a >= ' ') && (a <= '~'))

Link: https://lore.kernel.org/r/20210228055645.22253-8-chaitanya.kulkarni@wdc.com
Link: https://lore.kernel.org/r/20210228055645.22253-9-chaitanya.kulkarni@wdc.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_stat.c

@@ -31,9 +31,6 @@
 #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
 #endif
 
-#define NONE		"None"
-#define ISPRINT(a)   ((a >= ' ') && (a <= '~'))
-
 #define SCSI_LU_INDEX			1
 #define LU_COUNT			1