Fetch country code information from Device sysfs path

HID devices report the country code via sysfs. Need to read it
and pass it and save it as a member variable to InputDevice

In subsequent CLs will use it to auto-detect a layout for PK.
More information in DD: go/pk_auto_layout_detection

Test: atest inputflinger_tests:InputReaderTest
Bug: 242715614
Change-Id: I73ca7518dbee3e563c41024bb3ed41261c8d7846