tcm_qla2xxx: Remove duplicate header file inclusion

ctype.h and string.h header files were included more than once.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/scsi/qla2xxx/tcm_qla2xxx.c

@@ -38,8 +38,6 @@
 #include <linux/string.h>
 #include <linux/configfs.h>
 #include <linux/ctype.h>
-#include <linux/string.h>
-#include <linux/ctype.h>
 #include <asm/unaligned.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_host.h>