[SCSI] sd: DIF: Fix tagging on platforms with signed char

Switch tag arrays to u8 to prevent problems on platforms with signed
char.

Reported-by: Tim LaBerge <tim.laberge@Quantum.Com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sd_dif.c

@@ -142,7 +142,7 @@ static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
 static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors)
 {
 	struct sd_dif_tuple *sdt = prot;
-	char *tag = tag_buf;
+	u8 *tag = tag_buf;
 	unsigned int i, j;
 
 	for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
@@ -154,7 +154,7 @@ static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors
 static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors)
 {
 	struct sd_dif_tuple *sdt = prot;
-	char *tag = tag_buf;
+	u8 *tag = tag_buf;
 	unsigned int i, j;
 
 	for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
@@ -256,7 +256,7 @@ static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
 static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors)
 {
 	struct sd_dif_tuple *sdt = prot;
-	char *tag = tag_buf;
+	u8 *tag = tag_buf;
 	unsigned int i, j;
 
 	for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) {
@@ -269,7 +269,7 @@ static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors
 static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors)
 {
 	struct sd_dif_tuple *sdt = prot;
-	char *tag = tag_buf;
+	u8 *tag = tag_buf;
 	unsigned int i, j;
 
 	for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {