--- Comment #7 from Takashi Iwai email@example.com --- Indeed the repo seems to have multiple *.bin files for different versions, and one must copy it somehow to the right place.
In your case, try to find '*.bin' file under /lib/firmware/ath11k/QCA6390/hw2.0, and copy or symlink to /lib/firmware/ath11k/QCA6390/hw2.0 directory. As far as I see, multiple amss.bin and m3.bin are found:
QCA6390/hw2.0/msm/1.0.1.c1.2/WLAN.HST.1.0.1.c1.2-00014-QCAHSTSWPL_SILICONZ-1/m3.bin QCA6390/hw2.0/1.0.1/WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1/amss.bin QCA6390/hw2.0/1.0.1/WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1/m3.bin QCA6390/hw2.0/1.0.1/WLAN.HST.1.0.1-01230-QCAHSTSWPLZ_V2_TO_X86-1/m3.bin and you'll need to choose one of them.
I have no idea what each subidrectory indicates exactly, so it'll be just a guess work.