libacpi: Pass missing --dm_version to mk_dsdt

Commit 19ab8356ab ("tools: remove support for running a guest with
qemu-traditional") made passing --dm_version to mk_dsdt mandatory on
x86 but didn't fix all the invocations of it.

The previous default was qemu-xen-traditional so with that removed set
the dm_version to qemu-xen for this invocation.

Without this change, Xen fails to build on x86 when using
--enable-rombios.

Fixes: 19ab8356ab ("tools: remove support for running a guest with qemu-traditional")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

tools/libacpi/Makefile

@@ -51,7 +51,7 @@ $(ACPI_BUILD_DIR)/dsdt_%cpu.asl: dsdt.asl dsdt_acpi_info.asl  $(MK_DSDT)
 	# Remove last bracket
 	awk 'NR > 1 {print s} {s=$$0}' $< > $@.$(TMP_SUFFIX)
 	cat dsdt_acpi_info.asl >> $@.$(TMP_SUFFIX)
-	$(MK_DSDT) --debug=$(debug) --maxcpu $*  >> $@.$(TMP_SUFFIX)
+	$(MK_DSDT) --debug=$(debug) --maxcpu $* --dm-version qemu-xen >> $@.$(TMP_SUFFIX)
 	mv -f $@.$(TMP_SUFFIX) $@
 
 $(ACPI_BUILD_DIR)/dsdt_pvh.asl: dsdt_acpi_info.asl $(MK_DSDT)