[arm64,armhf] Enable SND_SOC_WM8731_I2C and COMMON_CLK_SI5351 as module

Enable drivers for wolfson wm8731 audio codec and common clock of Silicon Labs Si5351a/b/c i2c programmable clock generator as these are used in zBitx[1] sBitx[2] radio transceivers which are widely used and have an active community of over ~7,000 members[3].

These transceivers running Debian with Raspberry Pi Foundation's downstream kernel and I was trying to use Debian kernel and found these driver configs missing enabling these makes it easier for the transition and also a possibility to use/build pure Debian images for these radio transceivers.

[1] https://www.hfsignals.com/index.php/zbitx/ [2] https://www.hfsignals.com/index.php/sbitx-v3/ [3] https://groups.io/g/BITX20

Signed-off-by: Kurva Prashanth krvprashanth@riseup.net