received scan start failure event with the last two firmware

[g]

I’m seeing an issue with the ath12k driver when using certain recent 
firmware versions.
With the latest firmware, I get the following error:

|received scan start failure event|

If I manually restart the driver, sometimes scanning works, but other 
(most often) times it fails with this same error.

Affected firmware versions:

- |WLAN.HMT.1.1.c5-00284.1-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3|

|- ||WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3|

Working firmware version:

|fw_build_id 
QC_IMAGE_VERSION_STRING=WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3|

With the working firmware, scanning and connect works every time.

I am currently testing on the very latest Linux kernel from mainline:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=37816488247ddddbc3de113c78c83572274b1e2e