MT#57422 Properly move the pointer in the `read_param()`

It's been noticed that we have an improper implementation,
which attempts to move the pointer to the char array like this:
`input = param_size + 1;`

It's not right, it should be like that:
`input += (param_size + 1);`

Change-Id: Ia924a398cb37a64a06dfa385db6a0409f1e93e82

core/plug-in/opus/opus.c

@@ -186,7 +186,8 @@ static char* read_param(char* input, const char *param, char** param_value)
   if (*(input+param_size) != '=')
     return input;
 
-  input=param_size+1;
+  /* move by the param_size + 1 */
+  input += (param_size + 1);
 
   /* Found and discarded a matching parameter */
   *param_value = input;