Integrate meta-seco-imx/kirkstone-gm_sdma

Commit: edgehog/layers/seco/meta-seco-imx@4b98ac1f

[KERNEL][FIRMWARE] add i.MX{6,8} sdma firmware blob inside kernel image

The sdma firmware takes ~1 minute to load from filesystem at boot, causing a kernel panic or lockup whenever the dma is used (read/write from a serial port, aplay...) before the loading is complete. Allow early loading of the firmware blob by including it into the kernel binary, so the dma is ready when needed.