tools/testing/cxl: Add "Get Security State" opcode support

tools/testing/cxl: Add "Get Security State" opcode support

Add the emulation support for handling "Get Security State" opcode for a
CXL memory device for the cxl_test. The function will copy back device
security state bitmask to the output payload.

The security state data is added as platform_data for the mock mem device.

Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166983610177.2734609.4953959949148428755.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>