change vector constructor for gcc-14

gcc-14, with the latest Yocto sync, fails with the following compile
failure:

```
| ../git/ipmbbridged.cpp:724:34: error: value computed is not used [-Werror=unused-value]
|   724 |     std::vector<uint8_t> buffer(0);
```

Attempt using the default constructor, which should be equivalent,
instead.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I2d79813a52354bb00d992d6edfd9e2cc3a3ceacf
1 file changed