scsi: ufs: sysfs: string descriptors

This patch introduces a sysfs group entry for the UFS string descriptors.
The group adds "string_descriptors" folder under the UFS driver
sysfs entry (/sys/bus/platform/drivers/ufshcd/*). The folder will contain
5 files that will show string values defined by the UFS spec:
a manufacturer name, a product name, an OEM id, a serial number and a
product revision.  The full information about the string descriptors
could be found at UFS specifications 2.1.

Signed-off-by: Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b88fcf7..9cfdd8e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2873,11 +2873,11 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba,
  * The buf_len parameter will contain, on return, the length parameter
  * received on the response.
  */
-static int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
-					 enum query_opcode opcode,
-					 enum desc_idn idn, u8 index,
-					 u8 selector,
-					 u8 *desc_buf, int *buf_len)
+int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
+				  enum query_opcode opcode,
+				  enum desc_idn idn, u8 index,
+				  u8 selector,
+				  u8 *desc_buf, int *buf_len)
 {
 	int err;
 	int retries;
@@ -3093,8 +3093,8 @@ static int ufshcd_read_device_desc(struct ufs_hba *hba, u8 *buf, u32 size)
  * Return 0 in case of success, non-zero otherwise
  */
 #define ASCII_STD true
-static int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
-				   u8 *buf, u32 size, bool ascii)
+int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
+			    u8 *buf, u32 size, bool ascii)
 {
 	int err = 0;