qcacld-3.0: Cleanup unused variables introduced via LA.UM.9.12.r1-08400

Subsequent to 0e74ab4 ("qcacld-3.0: Merge tag
'LA.UM.9.12.r1-08400-SMxx50.0' into neutrino-msm-hotdogb-4.14")

These are likely related to disabled debugging functions or are
otherwise guarded by configs which we do not use. Mark as
__maybe_unused to keep the code intact and retain theoretical
functionality rather than nuking these variables outright.

This fixes the following compilation errors:

../drivers/staging/qcacld-3.0/core/mac/src/pe/lim/lim_send_management_frames.c:5385:19: error: unused variable 'fc' [-Werror,-Wunused-variable]
        tpSirMacFrameCtl fc = (tpSirMacFrameCtl)frame;
                         ^

../drivers/staging/qcacld-3.0/core/mac/src/pe/lim/lim_utils.c:1286:22: error: unused variable 'lim_params' [-Werror,-Wunused-variable]
                tLimNoShortParams *lim_params =
                                   ^

[@0ctobot: Restore 'third_index' variable to it's new location,
reverting commit 3d3d5ae ("qcacmn: Remove unused 'third_index' variable")]
Signed-off-by: Adam W. Willis <return.of.octobot@gmail.com>

drivers/staging/qcacld-3.0/components/cmn_services/policy_mgr/src/wlan_policy_mgr_pcl.c

@@ -752,6 +752,7 @@ QDF_STATUS policy_mgr_get_pcl(struct wlan_objmgr_psoc *psoc,
 	uint32_t num_connections = 0;
 	enum policy_mgr_conc_priority_mode first_index = 0;
 	enum policy_mgr_one_connection_mode second_index = 0;
+	enum policy_mgr_two_connection_mode third_index = 0;
 	enum policy_mgr_pcl_type pcl = PM_NONE;
 	enum policy_mgr_conc_priority_mode conc_system_pref = 0;
 	struct policy_mgr_psoc_priv_obj *pm_ctx;

drivers/staging/qcacld-3.0/core/mac/src/pe/lim/lim_send_management_frames.c

@@ -5382,7 +5382,7 @@ QDF_STATUS lim_send_delba_action_frame(struct mac_context *mac_ctx,
 static void lim_tx_mgmt_frame(struct mac_context *mac_ctx, uint8_t vdev_id,
 			      uint32_t msg_len, void *packet, uint8_t *frame)
 {
-	tpSirMacFrameCtl fc = (tpSirMacFrameCtl)frame;
+	tpSirMacFrameCtl fc __maybe_unused = (tpSirMacFrameCtl)frame;
 	QDF_STATUS qdf_status;
 	struct pe_session *session;
 	uint16_t auth_ack_status;

drivers/staging/qcacld-3.0/core/mac/src/pe/lim/lim_utils.c

@@ -1283,7 +1283,7 @@ lim_update_short_preamble(struct mac_context *mac_ctx, tSirMacAddr peer_mac_addr
 	}
 
 	if (i >= LIM_PROT_STA_CACHE_SIZE) {
-		tLimNoShortParams *lim_params =
+		tLimNoShortParams *lim_params __maybe_unused =
 				&psession_entry->gLimNoShortParams;
 		if (LIM_IS_AP_ROLE(psession_entry)) {
 #ifdef WLAN_DEBUG