wifi: ath12k: Restructure ahb.c into common and Wi-Fi 7 specific modules

wifi: ath12k: Restructure ahb.c into common and Wi-Fi 7 specific modules

Split ahb.c into a common module (ahb.c) and a Wi-Fi 7 specific module
(ahb_wifi7.c). Retain shared logic-such as probe and initialization
sequences-in ahb.c to support reuse across hardware families.
Move Wi-Fi 7 specific initialization and configuration routines to
ahb_wifi7.c and register them via callbacks.
This modular approach improves code organization and prepares the
driver for scalable support of additional hardware families.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
Tested-on: IPQ5332 hw1.0 AHB WLAN.WBE.1.3.1-00130-QCAHKSWPL_SILICONZ-1

Signed-off-by: Kiran Venkatappa <quic_kiranv@quicinc.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20250812-ath12k-mod-v1-7-8c9b0eb9335d@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>