wifi: rtw89: sar: add skeleton for different configs by antenna

Some SAR sources, e.g. ACPI, may allow different SAR configs by antenna.
Previously, the minimum config between antennas was taken. Because there
are differences between HW design, different chips might have different
solutions to achieve this. So, it cannot be done through a single common
handling. Now, add the relevant skeleton for this purpose ahead.

First, add a flag into chip info to describe whether it has implemented
this function or not. Second, support to query SAR config for a given RF
path. With it, each chip can implement its own handling. Then, if a chip
declares to support this function, when it queries SAR config without a
given RF path, it gets a maximum config between antennas.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250326020643.14487-10-pkshih@realtek.com