wifi: iwlwifi: suppress printf warnings in tracing

This can't really be fixed due to the macro layout of
tracepoints (you'd need a special tracepoint macro for
when this is needed), so just suppress the warnings.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/iwl-devtrace.c

@@ -12,6 +12,7 @@
 #include "iwl-trans.h"
 
 #define CREATE_TRACE_POINTS
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
 #include "iwl-devtrace.h"
 
 EXPORT_TRACEPOINT_SYMBOL(iwlwifi_dev_ucode_event);