Fix warning as error for V2

Change-Id: I70cfd971fda629011ba1be84fef15afea196d393
diff --git a/mbtk/libmbtk_lib_v2/ril/ril_utils.c b/mbtk/libmbtk_lib_v2/ril/ril_utils.c
index 9c39019..236c06f 100755
--- a/mbtk/libmbtk_lib_v2/ril/ril_utils.c
+++ b/mbtk/libmbtk_lib_v2/ril/ril_utils.c
@@ -157,12 +157,12 @@
 */
 int str_2_ipv6(const void *ip_str, void *ipv6)
 {
-    const uint8 *ptr = (const uint8*)ip_str;
+    const char *ptr = (const char*)ip_str;
     uint8 *ipv6_ptr = (uint8*)ipv6;
     ipv6_ptr[0] = (uint8)atoi(ptr);
     int i = 1;
     while(i < 16) {
-        ptr = (const uint8*)strstr(ptr, ".");
+        ptr = (const char*)strstr(ptr, ".");
         if(ptr == NULL)
             return -1;
         ptr++;
@@ -183,8 +183,8 @@
     int i = 0;
     int index = 0;
     while(i < 16) {
-        index += sprintf(ipv6_ptr + index, "%02x%02x", ptr[i], ptr[i + 1]);
-        index += sprintf(ipv6_ptr + index, ":");
+        index += sprintf((char*)ipv6_ptr + index, "%02x%02x", ptr[i], ptr[i + 1]);
+        index += sprintf((char*)ipv6_ptr + index, ":");
         i += 2;
     }