wifi: rtw89: chan: introduce new helper to get entity current configuration

wifi: rtw89: chan: introduce new helper to get entity current configuration

The original helper can only queries target channel, but cannot determine
current role's status, e.g. is it MLD or not. These things should be a set.
Adding more and more helpers to query them individually without synchronous
doesn't seem right. Introduce a new helper to query current channel set and
role status.

Besides, when single channel, e.g. MLO_2_PLUS_0_1RF and MLO_0_PLUS_2_1RF,
the target channel pointer will be duplicated to fill the returned channel
set. So, some callers can save trivial things for these cases. The returned
channels will be non-NULL, so callers don't need trivial NULL check either.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260420034051.17666-16-pkshih@realtek.com