staging: rtl8723bs: remove get_monotonic_boottime()

get_monotonic_boottime() is deprecated because it uses the
old 'timespec' structure. This replaces one of the last callers
with a call to ktime_get_boottime, which also simplifies it
a bit by avoiding a double conversion.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Quytelda Kahja <quytelda@tamalin.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c

@@ -233,13 +233,6 @@ static int rtw_ieee80211_channel_to_frequency(int chan, int band)
 	return 0; /* not supported */
 }
 
-static u64 rtw_get_systime_us(void)
-{
-	struct timespec ts;
-	get_monotonic_boottime(&ts);
-	return ((u64)ts.tv_sec*1000000) + ts.tv_nsec / 1000;
-}
-
 #define MAX_BSSINFO_LEN 1000
 struct cfg80211_bss *rtw_cfg80211_inform_bss(struct adapter *padapter, struct wlan_network *pnetwork)
 {
@@ -331,7 +324,7 @@ struct cfg80211_bss *rtw_cfg80211_inform_bss(struct adapter *padapter, struct wl
 
 	notify_channel = ieee80211_get_channel(wiphy, freq);
 
-	notify_timestamp = rtw_get_systime_us();
+	notify_timestamp = ktime_to_us(ktime_get_boottime());
 
 	notify_interval = le16_to_cpu(*(__le16 *)rtw_get_beacon_interval_from_ie(pnetwork->network.IEs));
 	notify_capability = le16_to_cpu(*(__le16 *)rtw_get_capability_from_ie(pnetwork->network.IEs));