clang-tidy-21: uninitialized-const-pointer warnings

Fix a few clang warnings raised with clang-tidy-21:

```
../tests/dsp/platform.cpp:917:46: error: variable 'effecter_value' is uninitialized when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer]
  917 |         0, 0, 6, reinterpret_cast<uint8_t*>(&effecter_value), request,
../tests/dsp/firmware_update.cpp:4837:47: error: variable 'data' is uninitialized when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer]
 4837 |     rc = decode_pldm_firmware_update_package(&data, sizeof(data), nullptr, &hdr,
```

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I468d2a1db894cf8ea0e72cd44b6fdc6c9130607d
diff --git a/tests/dsp/platform.cpp b/tests/dsp/platform.cpp
index 1760bcb..c7a0abf 100644
--- a/tests/dsp/platform.cpp
+++ b/tests/dsp/platform.cpp
@@ -911,7 +911,7 @@
         0, 0, 0, NULL, NULL, PLDM_SET_NUMERIC_EFFECTER_VALUE_MIN_REQ_BYTES);
     EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
 
-    uint16_t effecter_value;
+    uint16_t effecter_value = 0;
     rc = encode_set_numeric_effecter_value_req(
         // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast)
         0, 0, 6, reinterpret_cast<uint8_t*>(&effecter_value), request,