libpldm: Change hexadecimal literals to lowercase

As per a comment at [1].

The change was generated with the following:

```
sed -Ei 's/0[xX]([0-9]*[A-F][0-9]*)+/\L\0/g' $(git ls-files)
```

[1]: https://gerrit.openbmc.org/c/openbmc/libpldm/+/69192

Change-Id: Ib0a41dfaf626aec3167e773262883f9c1de797b2
Signed-off-by: Pavithra Barithaya <pavithra.b@ibm.com>
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/tests/oem/meta/libpldm_fileio_test.cpp b/tests/oem/meta/libpldm_fileio_test.cpp
index 663ed65..de4ba81 100644
--- a/tests/oem/meta/libpldm_fileio_test.cpp
+++ b/tests/oem/meta/libpldm_fileio_test.cpp
@@ -16,7 +16,7 @@
     struct pldm_msgbuf* ctx = &_ctx;
     uint8_t fileHandle = 0x00;
     int32_t dataLengthLE = 0x04;
-    uint8_t postCode[4] = {0x93, 0xE0, 0x00, 0xEA};
+    uint8_t postCode[4] = {0x93, 0xe0, 0x00, 0xea};
 
     constexpr auto hdrSize = sizeof(pldm_msg_hdr);