I have experienced the same failure of the "voice search" function in both Google Maps and the Google Search app after the upgrade of my Blackberry 9930 on Verizon to Blackberry OS 7.1.

 

The really insidious part of the problem, however, is that attempted use of the "voice search" function will disable or dramatically mute the phone ringer, no matter what the ringer profile is, and I have no visual indication that the ringer is off or muted.  A battery pull or soft reset via the [alt] - [right shift] - [del] combination is the only thing that appears to be able to restore the ringer to normal operation. I have disabled the voice search function in the Google Search app options menu to prevent me from accidentally trying to use it, but there appears to be no such option to disable the voice search function in the Google Maps app, so I'll just have to remember to not try using it until Google fixes the problem.