asoc: sdm670: add/remove flag ignore_pmdown_time for RX/TX DAIs

- During PCM close, the AIF power down will be delayed if
ignore_pmdown_time flag is not set. Set this flag for ultrasound RX DAI
to avoid delay in PCM close which causes slimbus overflow.
- Flag ignore_pmdown_time is only required to be set for RX DAIs.
Add this flag for RX DAIs that don't have it and remove this
flag for TX DAIs that have it in sdm670 machine driver.

CRs-Fixed: 2166356
Change-Id: I794ee96fb96fe04091ce73f0b48f84ebf119256c
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>