wifi: nl80211: make nl80211_check_scan_flags() type safe

The cast from void * here coupled with the boolean argument
on what to cast to is confusing and really not needed, just
split the code and make a type-safe interface. It seems to
even reduce the code size slightly, at least on x86-64.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250609213231.bdb3c96570b0.Ia153e6ce06dc9a636ff5bcc1d52468a1afd06e13@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>