asoc: bolero: add support to enable VA MCLK MUX select on Kona

VA macro is currently lacking capability to dynamically select
MCLK on Kona. Add support in VA macro driver to read MUX select
property from DT to enable dynamic MCLK MUX select.

Change-Id: I46d0b760119a2d8c2ed754ae9cb43ba717fa300b
Signed-off-by: Xiaoyu Ye <benyxy@codeaurora.org>