asoc: bolero: switch clk to VA_CLK for LPI SVA

When switching TX_CLK to VA_CLK, there could be some
IRQ missing with current design. Switch the clk in bolero
to avoid the corner case.

Change-Id: Iec5cac16e026e4e46646894c546f1acb3fce4fa8
Signed-off-by: Meng Wang <mengw@codeaurora.org>