x86, fpu: Shift "fpu_counter = 0" from copy_thread() to arch_dup_task_struct()

Cosmetic, but I think thread.fpu_counter should be initialized in
arch_dup_task_struct() too, along with other "fpu" variables. And
probably it make sense to turn it into thread.fpu->counter.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20140902175730.GA21669@redhat.com
Reviewed-by: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/process.c

@@ -66,6 +66,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
 	*dst = *src;
 
+	dst->thread.fpu_counter = 0;
 	dst->thread.fpu.has_fpu = 0;
 	dst->thread.fpu.last_cpu = ~0;
 	dst->thread.fpu.state = NULL;

arch/x86/kernel/process_32.c

@@ -152,7 +152,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 		childregs->orig_ax = -1;
 		childregs->cs = __KERNEL_CS | get_kernel_rpl();
 		childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
-		p->thread.fpu_counter = 0;
 		p->thread.io_bitmap_ptr = NULL;
 		memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 		return 0;
@@ -165,7 +164,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 	p->thread.ip = (unsigned long) ret_from_fork;
 	task_user_gs(p) = get_user_gs(current_pt_regs());
 
-	p->thread.fpu_counter = 0;
 	p->thread.io_bitmap_ptr = NULL;
 	tsk = current;
 	err = -ENOMEM;

arch/x86/kernel/process_64.c

@@ -163,7 +163,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 	p->thread.sp = (unsigned long) childregs;
 	p->thread.usersp = me->thread.usersp;
 	set_tsk_thread_flag(p, TIF_FORK);
-	p->thread.fpu_counter = 0;
 	p->thread.io_bitmap_ptr = NULL;
 
 	savesegment(gs, p->thread.gsindex);