xen/tools: fix substitution of __align8__ uint64_t inside of headers

xen/tools: fix substitution of __align8__ uint64_t inside of headers

The current seedery doesn't work with BSD sed, so remove the try to match
int64_t also (since there's none at the moment). Also, apply the same
treatment to all arch headers, currently this is only done to x86_64
headers.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>