The i.MX6 and i.MX7 are both 32bit ARM processor, they use the same toolchain. But the i.MX8MQ is 64bit ARM processor, so it’s toolchain is different from that of i.MX6/7.
Using MACHINE=imx8mqevk to export ARM64 toolchain
Details you can see the section 2. Exporting 4.9.88 toolchain from Freescale Yocto BSPDetailed Operations For Standalone On Linux BSP of I.MX Processors Hope this can do some help for you.