Change vector_entry names to match tftf code style

Change the exception vector names from CamelCase to lowercase with
underscores to better match the tftf code style.

Change-Id: Ieffc54edc12cf960af8bca1de36848e7e607d4a2
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
2 files changed