asoc: wcd9378: change the tx clk scale for different swr clk

when swr clk is 48Mhz, the swr base clk and clk scale
should be 19.2Mhz and DIV4.
when swr clk is 96Mhz, the swr base clk and clk scale
should be 19.2Mhz and DIV2.

Change-Id: I5beda01b024946cd7b54785ecfab91e3d0edc94f
Signed-off-by: Yuhui Zhao <quic_yuhuzhao@quicinc.com>