[Remove Mbox3 UCM] Request to revert pull 237

[ManuLinares]

#237

The SplitPCM adds not only latency, #238 but other general issues when streaming, etc.

So I propose removing the UCM profile.

[perexg]

The issues should be debugged (probably report this in alsa-lib with some debug info - the best way is to reproduce the issue without additional software like sound servers). Also, UCM is capable to avoid using the share plugin from alsa-lib and the sound server can obtain only information for the channel split operation. And for the last, users can always select the direct UCM profile.