Revert float capability for downmixer

Revert floating point processing on downmixer.

This commits partially reverts d7d013446a64c6de9f0f2dfe098a721b140e0b48
Bug: 63760315

Test: Play multichannel movie
Change-Id: I16edf8767e02ef5d8ff63f52e8d1222ce0d09e22
1 file changed