fireball: remove unused overlays

Phone overlays have moved to services/Telephony and these configurations
no longer apply.

MMS overlays for maxMessageSize and enableMultipartSMS duplicate base
configuration, no need for overlay.

Change-Id: I4252c00ddeb405d7149c9efa2c9f35049dac887e
fireball: overlay services/Telephony options

Change-Id: I3b632931ab2e4d6eb04ce66f46db6de9270c0b99