qcacld-3.0: Remove unused wlan_ptp_gettime() stack variable

There are two different implementations of wlan_ptp_gettime()
depending upon the version of the Linux Kernel. The implementation
for versions before Linux Kernel 4.1 has an unused stack variable,
tsf_reg_read_enabled. This can result in compiler warnings, so
remove it.

Change-Id: I1ed7e15ff0cf8867356e8cea39bff5f4ee362877
CRs-Fixed: 3426059

core/hdd/src/wlan_hdd_tsf.c

@@ -2871,7 +2871,6 @@ static int wlan_ptp_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
 	uint64_t host_time, target_time = 0;
 	struct hdd_context *hdd_ctx;
 	struct hdd_adapter *adapter;
-	uint32_t tsf_reg_read_enabled;
 	struct osif_psoc_sync *psoc_sync;
 	int errno, status = 0;