x86/asm: Remove the xyz_cfi macros from dwarf2.h

x86/asm: Remove the xyz_cfi macros from dwarf2.h

They are currently unused, and I don't think that anyone was
ever particularly happy with them.  They had the unfortunate
property that they made it easy to CFI-annotate things without
thinking about them -- when pushing, do you want to just update
the CFA offset, or do you also want to update the saved location
of the register being pushed?

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
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/1447bfbd10bb268b4593b32534ecefa1f4df287e.1444696194.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>