x86/fpu: Rename restore_xstate_sig() to fpu__restore_sig()

restore_xstate_sig() is a misnomer: it's not limited to 'xstate' at all,
it is the high level 'restore FPU state from a signal frame' function
that works with all legacy FPU formats as well.

Rename it (and its helper) accordingly, and also move it to the
fpu__*() namespace.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
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>
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index d6ac461..d6cfbda 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -497,14 +497,14 @@
  * Signal frame handlers...
  */
 extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fx, int size);
-extern int __restore_xstate_sig(void __user *buf, void __user *fx, int size);
+extern int __fpu__restore_sig(void __user *buf, void __user *fx, int size);
 
 static inline int xstate_sigframe_size(void)
 {
 	return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
 }
 
-static inline int restore_xstate_sig(void __user *buf, int ia32_frame)
+static inline int fpu__restore_sig(void __user *buf, int ia32_frame)
 {
 	void __user *buf_fx = buf;
 	int size = xstate_sigframe_size();
@@ -514,7 +514,7 @@
 		size += sizeof(struct i387_fsave_struct);
 	}
 
-	return __restore_xstate_sig(buf, buf_fx, size);
+	return __fpu__restore_sig(buf, buf_fx, size);
 }
 
 /*