iwlwifi: reduce debug ifdefs using the optimiser

Instead of using #ifdef CONFIG_IWLWIFI_DEBUG, remove the
iwlwifi_mod_params.debug_level variable completely and
make iwl_have_debug_level() always return false in the
non-debug case. This way, the optimiser will elide all
code for it automatically without having to add #ifdefs.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-debug.h b/drivers/net/wireless/iwlwifi/iwl-debug.h
index 8cf5db7..7edb851 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debug.h
+++ b/drivers/net/wireless/iwlwifi/iwl-debug.h
@@ -34,7 +34,11 @@
 
 static inline bool iwl_have_debug_level(u32 level)
 {
+#ifdef CONFIG_IWLWIFI_DEBUG
 	return iwlwifi_mod_params.debug_level & level;
+#else
+	return false;
+#endif
 }
 
 void __iwl_err(struct device *dev, bool rfkill_prefix, bool only_trace,