x86: fix compat guest handling of XENPF_enter_acpi_sleep

x86: fix compat guest handling of XENPF_enter_acpi_sleep

Rather than blindly defining the native name to the compat one, when
we want to pass the compat structure to a native function we ought to
verify that their layouts match. With a respective xlat.lst entry
there's then also no need anymore to do such aliasing.

While cleaaning up that file I also noticed that the Cx and Px
interface handling here has quite a few unnecessary #define-s - delete
them.

Signed-off-by: Jan Beulich <jbeulich@suse.com>