policy_hal: Use right cflags to support Compress VoIP

COMPRESS_VOIP_ENABLED is defined as false by default
in makefile even if COMPRESS_VOIP feature is applicable.
Then VoIP rx and tone playback both are configured with
direct flag, and reusing same direct output. When tone
stop, VoIP rx also is also stopped.

Fix by correcting error in makefile to use right cflags
to support Compress VoIP.

CRs-Fixed: 2115554
Change-Id: Ie06f4859ed6c2c74d48c89bb7cf588df1dd3cff7