qcacld-3.0: Remove sapCleanupAllChannelList() prototype

sap_api.h currently exports sapCleanupAllChannelList() but the
implementation of that function is no longer preset, so remove the
obsolete prototype.

Change-Id: Ic7fae1985edebde3784e33aed09d011acbcd251d
CRs-Fixed: 2108350

core/sap/inc/sap_api.h

@@ -883,7 +883,6 @@ typedef struct {
 } sapSafeChannelType;
 #endif /* FEATURE_WLAN_CH_AVOID */
 void sap_cleanup_channel_list(void *sapContext);
-void sapCleanupAllChannelList(void);
 
 /**
  * sap_is_auto_channel_select() - is channel AUTO_CHANNEL_SELECT