user_channel: Rewriting ipmiUserSetUserName API

Rewriting ipmiUserSetUserName API

Tested:
Verified using ipmitool commands.
Command: ipmitool user set name 4 user4
Response:    //Success
Command: ipmitool user set password 4 asdf1234
Response: Set User Password command successful (user 4)
Command: ipmitool user priv 4 0x03 1
Response: Set Privilege Level command successful (user 4)
Command: ipmitool user set name 14 user13asdfghkjlqwert
Response: Username is too long (> 16 bytes)
Command: ipmitool -I lanplus -C 3 -p 623 -U root -P <password> -H
         <BMC-IP> user set name 8 WIJGueNKd
Response:                       //Success
Command: ipmitool user list 1 //User list for channel 1
1   root             false   true       true       ADMINISTRATOR
2   user2            true    false      false      USER
3   user3            true    false      false      NO ACCESS
4   user4            true    false      false      OPERATOR
5   WIJGueNK         true    false      false      NO ACCESS
6   WIJGueNKb        true    false      false      NO ACCESS
7   WIJGueNKc        true    false      false      NO ACCESS
8   WIJGueNKd        true    false      false      NO ACCESS
9                    true    false      false      NO ACCESS
10                   true    false      false      NO ACCESS

Signed-off-by: jayaprakash Mutyala <mutyalax.jayaprakash@intel.com>
Change-Id: I41c091f6d9aaf54326295d1e80e16db521b2e23d
diff --git a/user_channel/user_layer.hpp b/user_channel/user_layer.hpp
index b0d0d4c..0639474 100644
--- a/user_channel/user_layer.hpp
+++ b/user_channel/user_layer.hpp
@@ -143,6 +143,15 @@
  */
 Cc ipmiUserSetUserName(const uint8_t userId, const char* userName);
 
+/** @brief set's user name
+ *
+ *  @param[in] userId - user id
+ *  @param[in] userName - user name
+ *
+ *  @return ccSuccess for success, others for failure.
+ */
+Cc ipmiUserSetUserName(const uint8_t userId, const std::string& userName);
+
 /** @brief set user password
  *
  *  @param[in] userId - user id