ath10k: fix possible bmi crash

While testing other things I've found that CE
items aren't cleared properly. This could lead to
null dereferences in BMI.

To prevent that make sure CE revoking clears the
nbytes value (which is used as a buffer completion
indication) and memset the entire CE rings when
(re)initializing.

Also make sure to check BMI xfer pointer and print
a splat instead of crashing the kernel.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: expose hw restart via debugfs

Until now it was possible to simulate soft and
hard fw crashes but it wasn't possible to trigger
an immediately hw restart itself (without the fw
crash).

This can be useful when stress testing hw
restarting stability, e.g. during heavy tx/rx
traffic.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
ath10k: speed up hw recovery

In some cases hw recovery was taking an absurdly
long time due to ath10k waiting for things that
would never really complete.

Instead of waiting for inevitable timeouts poke
all completions and wakequeues and check if it's
still worth waiting.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>