microblaze: exec: Remove redundant set_fs(USER_DS)

The address limit is already set in flush_old_exec() so this
set_fs(USER_DS) is redundant.
Signed-off-by: Mathias Krause <minipli@googlemail.com>

arch/microblaze/kernel/process.c

@@ -237,7 +237,6 @@ unsigned long get_wchan(struct task_struct *p)
 /* Set up a thread for executing a new program */
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
 {
-	set_fs(USER_DS);
 	regs->pc = pc;
 	regs->r1 = usp;
 	regs->pt_mode = 0;