libxc: switch xc_dom_elfloader to be used with HVMlite domains

libxc: switch xc_dom_elfloader to be used with HVMlite domains

Allow xc_dom_elfloader to report a guest type as hvm-3.0-x86_32 if it's
running inside of a HVM container and has the PHYS32_ENTRY elfnote set.

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>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>