ACPI / hotplug / PCI: Drop crit_sect locking

After recent PCI core changes related to the rescan/remove locking,
the code sections under crit_sect mutexes from ACPIPHP slot objects
are always executed under the general PCI rescan/remove lock.
For this reason, the crit_sect mutexes are simply redundant, so drop
them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>