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
hammerhead: lcd_kcal: remove control bit

Change-Id: Iba8dfd157406bbdeb0421e30c7dc495a0d377d0c