Revert "Packet-Loss Concealment (PLC) for supporting codecs."

This change introduced some fax test failures
that have not yet been addressed. So this is
not forgotten I'm submitting a change which
reverts it.

This reverts:
d56fc3b3.

ASTERISK-25629

Change-Id: Ibc2f23c38643f5a2c89cf8915ae2d805b81bc3d5