Add Advantech QCM6490 ASoC machine driver support

Add a new patch to enable Advantech QCM6490 ASoC machine driver in
the Qualcomm kernel. This patch integrates the driver configuration
into the kernel build to support audio on Advantech QCM6490-based
platforms.

Changes:
- Add 0001-ASoC-qcom-add-Advantech-QCM6490-machine-driver-suppo.patch
- Update linux-qcom-custom_%.bbappend to include the new patch

Signed-off-by: Darren Huang <[email protected]>

Author: advdarren