ACPI: remove unused acpi_op_bind and acpi_op_unbind

With commit f2a33cde55a03 "ACPI: Drop ACPI device .bind() and .unbind()
callbacks", acpi_op_bind and acpi_op_unbind are not used any more. So
remove them.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>