HammerHead : Add proximity wake flag

Change-Id: I78e677b20a03977d8180726dc64283658ce9c5f9
hammerhead: Make proximity check opt-in

This function's behavior is annoying and can even be
a deal-breaker for new or undiscerning CM users.

Change-Id: I51e43fd2adeaab79e74541fafadac95e16b267ff