ath10k: fix tracing build for ath10k_wmi_cmd

Commit be8b394390 ("ath10k: make WMI commands block by design") broke
the build if CONFIG_ATH10K_TRACING was enabled.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/trace.h

@@ -119,7 +119,7 @@ TRACE_EVENT(ath10k_wmi_cmd,
 		__field(unsigned int, id)
 		__field(size_t, buf_len)
 		__dynamic_array(u8, buf, buf_len)
-		__field(int ret)
+		__field(int, ret)
 	),
 
 	TP_fast_assign(