wifi: ath12k: delete mon reap timer

wifi: ath12k: delete mon reap timer

Currently mon reap timer is not used, and it is not needed anymore for
WCN7850.

So remove related code.

This change does not affect QCN9274, as the mon reap timer is not used
for QCN9274.

Signed-off-by: Kang Yang <kang.yang@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20250416022011.1935-1-kang.yang@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>