wifi: ath12k: Fix ath12k_dp_htt_tlv_iter()'s iter() signature

wifi: ath12k: Fix ath12k_dp_htt_tlv_iter()'s iter() signature

Per ath12k convention, a pointer to struct ath12k_base should be named
'ab'. However, the current signature of the 'iter' parameter of
ath12k_dp_htt_tlv_iter() uses 'ar'. Change it to use 'ab'.

No functional changes, compile tested only.

Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20260409-ath12k-htc-proto-v1-2-cda86d6355f1@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>