x86/fpu: Rename __thread_fpu_begin() to fpregs_activate()

Propagate the 'fpu->fpregs_active' naming to the high level
function that sets it.

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/fpu/core.c

@@ -368,9 +368,9 @@ void fpu__restore(void)
 		local_irq_disable();
 	}
 
-	/* Avoid __kernel_fpu_begin() right after __thread_fpu_begin() */
+	/* Avoid __kernel_fpu_begin() right after fpregs_activate() */
 	kernel_fpu_disable();
-	__thread_fpu_begin(fpu);
+	fpregs_activate(fpu);
 	if (unlikely(restore_fpu_checking(fpu))) {
 		fpu_reset_state(fpu);
 		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);