x86/percpu: Clean up <asm/percpu.h> vertical alignment details

 - Fix/unify misc vertical alignment inconsistencies

 - Make CPP macros look a bit more like C code by adding
   an empty line after local variable declaration blocks,
   and before final rvalue statements.

No change in code.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org