wifi: rtw89: pass chanctx_idx to rtw89_btc_{path_}phymap()

Originally, rtw89_btc_phymap() and rtw89_btc_path_phymap() access chan
with hard-code RTW89_CHANCTX_0. But, they are problematic when the chip
supports multiple channels.

So, change their prototype and pass chanctx_idx ahead. Let callers still
pass RTW89_CHANCTX_0 for now, but we will refine callers in the following.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240727080650.12195-8-pkshih@realtek.com