wifi: rtw89: debug: show txpwr table according to chip gen

Since current TX power stuffs are for ax chips, add a suffix `_ax` to
them. Then, when requested to show txpwr table, select table according
to chip generation first.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231003015446.14658-7-pkshih@realtek.com