cxl: Store the access coordinates for the generic ports

cxl: Store the access coordinates for the generic ports

Each CXL host bridge is represented by an ACPI0016 device. A generic port
device handle that is an ACPI device is represented by a string of
ACPI0016 device HID and UID. Create a device handle from the ACPI device
and retrieve the access coordinates from the stored memory targets. The
access coordinates are stored under the cxl_dport that is associated with
the CXL host bridge.

The access coordinates struct is dynamically allocated under cxl_dport in
order for code later on to detect whether the data exists or not.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/170319623196.2212653.17916695743464172534.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>