mfd: wcd9xxx: fix multi channel payload calculation

When multiple channels are used for a session (Rx/Tx), all bits in the
Rx/Tx port multichannel register needs to be Set. If a bit corresponding
to any channel is missing, the channel will not be aware that the other
channel (corresponding to the missing bit) is also part of the same group.
This will create ambiguity among the channels in the same PCM group and
will lead to shifting of Phase/delay in data in those channels.

CRs-fixed: 425803
Change-Id: Ie78ba82eeeb494db73a781e96b835361ef589a67
Signed-off-by: Banajit Goswami <bgoswa@codeaurora.org>