x86: adjustments to guest handle treatment

x86: adjustments to guest handle treatment

First of all avoid excessive conversions. copy_{from,to}_guest(), for
example, work fine with all of XEN_GUEST_HANDLE{,_64,_PARAM}().

Further
- do_physdev_op_compat() didn't use the param form for its parameter,
- {hap,shadow}_track_dirty_vram() wrongly used the param form,
- compat processor Px logic failed to check compatibility of native and
  compat structures not further converted.

As this eliminates all users of guest_handle_from_param() and as there's
no real need to allow for conversions in both directions, drop the
macros as well.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>