x86, asm: Thin down SAVE/RESTORE_* asm macros

Use dwarf2 cfi annotation macros, making SAVE/RESTORE_* marginally more
readable.

No functionality change.

Signed-off-by: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1306873314-32523-2-git-send-email-bp@alien8.de


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>