wifi: ath11k: relocate some Tx power related functions in mac.c

wifi: ath11k: relocate some Tx power related functions in mac.c

A forthcoming change necessitates that these functions be defined prior to
their usage. Therefore, relocate them now as a preparatory step for the
upcoming modifications.

Compile tested only.

Signed-off-by: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20251017-add_tx_power_insertion_support-v1-1-f08feacfca93@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>