wifi: rtw89: roc: dynamically handle link id and link instance index

wifi: rtw89: roc: dynamically handle link id and link instance index

Originally, a macro, RTW89_ROC_BY_LINK_INDEX, is used to decide the link
which deals with the ROC process. Before enabling MLO support, it's fine
to hard-code RTW89_ROC_BY_LINK_INDEX as 0 since the link instance-0 (on
HW-0) is always active. But, for the impending enablement of MLO support,
tweak the leaf functions to dynamically handle ROC link instance index.

Besides, in the follow-up, ROC caller will get a designated link and will
then drop RTW89_ROC_BY_LINK_INDEX.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250428112456.13165-10-pkshih@realtek.com