Change primary postcode interface to byte array

Test results:
```
root@bmc:~# busctl call xyz.openbmc_project.State.Boot.PostCode0 /xyz/openbmc_project/State/Boot/PostCode0 xyz.openbmc_project.State.Boot.PostCode GetPostCodes q 1 -j
{
        "type" : "a(ayay)",
        "data" : [
                [
                        [
                                [
                                        1,
                                        2,
                                        3,
                                        4,
                                        5,
                                        6,
                                        7,
                                        8,
                                        9
                                ],
                                []
                        ],
                        [
                                [
                                        17,
                                        18,
                                        19,
                                        20,
                                        21,
                                        22,
                                        23,
                                        24,
                                        25
                                ],
                                []
                        ],
                        [
                                [
                                        33,
                                        34,
                                        35,
                                        36,
                                        37,
                                        38,
                                        39,
                                        40,
                                        41
                                ],
                                []
                        ]
                ]
        ]
}
```

Change-Id: I81387df590c2c6781451c6dbcc030d48ca011eb6
Signed-off-by: Potin Lai <potin.lai@quantatw.com>
diff --git a/inc/post_code.hpp b/inc/post_code.hpp
index 26b5c48..db7533f 100644
--- a/inc/post_code.hpp
+++ b/inc/post_code.hpp
@@ -50,7 +50,7 @@
     }
 };
 using EventPtr = std::unique_ptr<sd_event, EventDeleter>;
-using primarycode_t = uint64_t;
+using primarycode_t = std::vector<uint8_t>;
 using secondarycode_t = std::vector<uint8_t>;
 using postcode_t = std::tuple<primarycode_t, secondarycode_t>;
 namespace fs = std::filesystem;
diff --git a/src/post_code.cpp b/src/post_code.cpp
index 037f293..6473562 100644
--- a/src/post_code.cpp
+++ b/src/post_code.cpp
@@ -119,16 +119,22 @@
             POSTCODE_DISPLAY_PATH + std::to_string(node);
 
         std::ofstream postCodeDisplayFile(postCodeDisplayPath);
-        postCodeDisplayFile << "0x" << std::setfill('0') << std::setw(2)
-                            << std::hex << std::get<0>(code);
+        postCodeDisplayFile << "0x" << std::setfill('0') << std::hex;
+        for (const auto& byte : std::get<0>(code))
+        {
+            postCodeDisplayFile << std::setw(2) << static_cast<int>(byte);
+        }
         postCodeDisplayFile.close();
     }
 
 #ifdef ENABLE_BIOS_POST_CODE_LOG
     uint64_t usTimeOffset = tsUS - firstPostCodeUsSinceEpoch;
     std::ostringstream hexCode;
-    hexCode << "0x" << std::setfill('0') << std::setw(2) << std::hex
-            << std::get<0>(code);
+    hexCode << "0x" << std::setfill('0') << std::hex;
+    for (const auto& byte : std::get<0>(code))
+    {
+        hexCode << std::setw(2) << static_cast<int>(byte);
+    }
 
     std::ostringstream timeOffsetStr;
     // Set Fixed-Point Notation