[IMX8MM][MYON2] Add support of Myon II i.MX8M Mini module

Add support of Myon II i.MX8M Mini module with ConXM carrier.

This MR contains changes ported from SECO NE Linux: seco-ne/kernel/linux-imx-kuk!442 (merged) and seco-ne/kernel/linux-imx-kuk!561 (merged). In particular:

• ported seconorth-myon2-conxm-hdmi and seconorth-myon2-conxm-atm0700l61ct device trees;
• added SECO version of rohm-bd718x7 driver with optional interrupts.

Other changes introduced in the MR:

• Added support of audio (wm8983 for V1R4, wm8962 for V2R1):
  • Imported changes for audio codecs from kuk kernel;
  • Cherry-picked commit from NXP kernel for imx-sdma to fix kernel crash when starting audio playback;
  • Added device tree overlays to switch audio codecs.
• Added missing SPI2 node in dts and fixed pinmuxing for it. Removed unused UART4;
• Fixed MMC enumeration;
• Added AT24 EEPROM and PCF8574A GPIO Expander in conxm.dtsi.