ath10k: update chirp value in pulse event

Firmware reports chirp status in phy error event if it's detected
and the chirp status is valuable to distinguish radar types.
So save it to use for DFS parttern detector.

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