ASoC: wcd9320: increase DMIC CLK drive-strength

Increase DMIC CLK drive-strength for WCD9320 codec from 2mA
to 4mA. This increase will improve setup and hold times for
DMICs in WCD9320 codec.

Change-Id: Id8603a994281b9c7f1a3eeb2d258ce2805f03575
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>