Support BootProgress's OemLastState

OemLastState get boot state value from PostCodes (Boot.Raw) and
display as hex string as below example.

"BootProgress": {
    "LastState": "OEM",
    "LastStateTime": "2024-11-14T18:16:44.549874+00:00",
    "OemLastState": "0x010000000010010000"
}

Tested:
1. Set boot progress code
   $> ipmitool raw 0x2c 0x02 0xae 0x01 0x00 0x00 0x00 0x00 \
      0x10 0x01 0x00 0x00

2. Check the progress code from the Redfish interface
   # /redfish/v1/Systems/system
   "BootProgress": {
       "LastState": "OEM",
       "LastStateTime": "2024-11-14T18:16:44.549874+00:00",
       "OemLastState": "0x010000000010010000"
   }

3. Run pass with Redfish-Service-Validator

Change-Id: Id3b76fc68d2f80ec6b26d6d351c2090da783b7cf
Signed-off-by: John Chung <john.chung@arm.com>