x86/entry/vm86: Clean up saved_fs/gs

x86/entry/vm86: Clean up saved_fs/gs

There is no need to save FS and non-lazy GS outside the 32-bit
regs.  Lazy GS still needs to be saved because it wasn't saved
on syscall entry.  Save it in the gs slot of regs32, which is
present but unused.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437354550-25858-2-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>