log: Fix up debug_cond() when LOG is enabled

At present debug() statements can cause debuf output to appear when LOG is
enabled but DEBUG is not. This is not intended and it seems that the
condition is wrong.

Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/log.h b/include/log.h
index 6ef891d..add3a1e 100644
--- a/include/log.h
+++ b/include/log.h
@@ -222,11 +222,14 @@
 #define _SPL_BUILD	0
 #endif
 
-#if !_DEBUG && CONFIG_IS_ENABLED(LOG)
+#if CONFIG_IS_ENABLED(LOG)
 
-#define debug_cond(cond, fmt, args...)			\
-({							\
-	log(LOG_CATEGORY, LOGL_DEBUG, fmt, ##args);	\
+#define debug_cond(cond, fmt, args...)					\
+({									\
+	if (cond)							\
+		log(LOG_CATEGORY,					\
+		    (enum log_level_t)(LOGL_FORCE_DEBUG | _LOG_DEBUG),	\
+		    fmt, ##args);					\
 })
 
 #else /* _DEBUG */