WCD9310 codec supports loopback through IIR filters. Either IIR1 or IIR2 can be used to setup loopback path. Add support and routing to enable loopback through IIR2 filter path CRs-fixed: 364236 Change-Id: I52cb455ad31aa129f81bac3852ac50d4a5a99bc2 Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org> Signed-off-by: Kiran Kandi <kkandi@codeaurora.org> (cherry picked from commit 8ba4446a571ed5f7033dc6cb651e19f5d9485abb)