wifi: mac80211: fix beacon interval calculation overflow

As we are converting from TU to usecs, a beacon interval of
100*1024 usecs will lead to integer wrapping. To fix change
to use a u32.

Fixes: 057d5f4 ("mac80211: sync dtim_count to TSF")
Signed-off-by: Lachlan Hodges <lachlan.hodges@morsemicro.com>
Link: https://patch.msgid.link/20250621123209.511796-1-lachlan.hodges@morsemicro.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Author: donnaskiez

net/mac80211/util.c

@@ -3884,7 +3884,7 @@ void ieee80211_recalc_dtim(struct ieee80211_local *local,
 {
 	u64 tsf = drv_get_tsf(local, sdata);
 	u64 dtim_count = 0;
-	u16 beacon_int = sdata->vif.bss_conf.beacon_int * 1024;
+	u32 beacon_int = sdata->vif.bss_conf.beacon_int * 1024;
 	u8 dtim_period = sdata->vif.bss_conf.dtim_period;
 	struct ps_data *ps;
 	u8 bcns_from_dtim;