eventlog: Rename eventlog SMBIOS files to avoid confusion

Having elog.{c,h} and eventlog.{c,h} is kind of silly, so this
renames the SMBIOS-specific files to reflect what they really
are.

BUG=none
BRANCH=none
TEST=compiled for nyan and rambi

Change-Id: I739418a3e0ebb91871d9986279ac614ff5344b3d
Reviewed-on: https://chromium-review.googlesource.com/196353
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
5 files changed