defconfig: msm: Sync up mdm-perf_defconfig with defaults

The mdm-perf_defconfig has a few stale config entries.  Sync it up with
the Kbuild defaults.

Change-Id: I088a993f41e6cd13eeb640d0d68aa8f59a649bac
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>