Revert "acpi: mark PMTIMER as unlocked"

This reverts commit 7070e085.

Commit message claims locking is not needed, but that appears
to not be true, seabios ehci driver runs into timekeeping problems
with this, see
	https://bugzilla.redhat.com/show_bug.cgi?id=1322713Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Message-id: 1460702609-25971-1-git-send-email-kraxel@redhat.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/acpi/core.c

@@ -536,7 +536,6 @@ void acpi_pm_tmr_init(ACPIREGS *ar, acpi_update_sci_fn update_sci,
     ar->tmr.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, acpi_pm_tmr_timer, ar);
     memory_region_init_io(&ar->tmr.io, memory_region_owner(parent),
                           &acpi_pm_tmr_ops, ar, "acpi-tmr", 4);
-    memory_region_clear_global_locking(&ar->tmr.io);
     memory_region_add_subregion(parent, 8, &ar->tmr.io);
 }