ath10k: print firmware version string during boot

Currently we don't print firmware version at all. Move the
current "firmware dowloaded" message later once firmware
has booted and include firmware version in the message.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: only warn about incompatible firmware versions

Most of the time it does more harm than good to halt the
driver initialisation if the firmware version is not
supported. For example, sometimes it's good to test
something from older versions etc. So just change the
check to a warning.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>