x86/hvm: Drop hvm_{vmx,svm} shorthands

x86/hvm: Drop hvm_{vmx,svm} shorthands

By making {vmx,svm} in hvm_vcpu into an anonymous union (consistent with
domain side of things), the hvm_{vmx,svm} defines can be dropped, and all code
refer to the correctly-named fields.  This means that the data hierachy is no
longer obscured from grep/cscope/tags/etc.

Reformat one comment and switch one bool_t to bool while making changes.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>