hostapd: Fix some compilation errors

If NEED_AP_MLME=y is not defined, compilation might
fail under some configurations:

src/ap/drv_callbacks.c:594:2: warning: implicit declaration of
function ‘hostapd_acs_completed’ [-Wimplicit-function-declaration]

src/ap/sta_info.c:253: undefined reference to `sae_clear_retransmit_timer'

Fix these errors by adding the missing hostapd_acs_completed() stub,
and defining NEED_AP_MLME in case of CONFIG_SAE.

Signed-off-by: Eliad Peller <eliad@wizery.com>

hostapd/Makefile

@@ -227,6 +227,7 @@ CFLAGS += -DCONFIG_SAE
 OBJS += ../src/common/sae.o
 NEED_ECC=y
 NEED_DH_GROUPS=y
+NEED_AP_MLME=y
 endif
 
 ifdef CONFIG_WNM

src/ap/hw_features.h

@@ -36,6 +36,11 @@ static inline int hostapd_get_hw_features(struct hostapd_iface *iface)
 	return -1;
 }
 
+static inline int hostapd_acs_completed(struct hostapd_iface *iface, int err)
+{
+	return -1;
+}
+
 static inline int hostapd_select_hw_mode(struct hostapd_iface *iface)
 {
 	return -100;