wifi: ath9k: ahb: do ioremap resource in one step

wifi: ath9k: ahb: do ioremap resource in one step

Simplifies probe slightly and adds extra error codes.

Switching from devm_ioremap to the platform variant ends up calling
devm_request_mem_region, which reserves the memory region for the
various wmacs. Per board, there is only one wmac and after some fairly
thorough analysis, there are no overlapping memory regions between wmacs
and other devices on the ahb.

Tested on a TP-Link Archer C7v2.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20250421040044.44887-1-rosenp@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>