x86/entry/32: Relax a pvops stub clobber specification

x86/entry/32: Relax a pvops stub clobber specification

The code at .Lrestore_nocheck does not make any assumptions on register
values, so all registers can be clobbered on code paths leading there.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@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/5894542B02000078001366C5@prv-mh.provo.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>