openrisc: Cleanup copy_thread_tls docs and comments

Previously copy_thread_tls was copy_thread and before that something
else.  Remove the documentation about the regs parameter that didn't
exist in either version.

Next, fix comment wrapping and details about how TLS pointer gets to the
copy_thread_tls function.
Signed-off-by: Stafford Horne <shorne@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

arch/openrisc/kernel/process.c

@@ -122,7 +122,6 @@ extern asmlinkage void ret_from_fork(void);
  * @usp: user stack pointer or fn for kernel thread
  * @arg: arg to fn for kernel thread; always NULL for userspace thread
  * @p: the newly created task
- * @regs: CPU context to copy for userspace thread; always NULL for kthread
  * @tls: the Thread Local Storage pointer for the new process
  *
  * At the top of a newly initialized kernel stack are two stacked pt_reg