x86: change assembly definition of paravirt_patch_site

To account for differences in x86_64, we change the macros that
create raw instances of the paravirt_patch_site struct.
We need to align 64-pointers to 64-bit boundaries, so we add an alignment
directive. Also, we need to make room for a word-sized pointer,
instead of a fixed 32-bit one

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>