x86/fpu: Remove failure paths from fpstate-alloc low level functions

Now that we always allocate the FPU context as part of task_struct there's
no need for separate allocations - remove them and their primary failure
handling code.

( Note that there's still secondary error codes that have become superfluous,
  those will be removed in separate patches. )

Move the somewhat misplaced setup_xstate_comp() call to the core.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/process.c

@@ -86,16 +86,6 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 	return fpu__copy(&dst->thread.fpu, &src->thread.fpu);
 }
 
-void arch_release_task_struct(struct task_struct *tsk)
-{
-	fpstate_free(&tsk->thread.fpu);
-}
-
-void arch_task_cache_init(void)
-{
-	fpstate_cache_init();
-}
-
 /*
  * Free current thread data structures etc..
  */