Add warn_non_spl() to show a message in U-Boot proper

SPL tends to be more space-constrained that U-Boot proper. Some error
messages are best suppressed in SPL. Add a macros to make this easy.

warn_non_spl() does nothing when built in SPL code.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/common.h

@@ -101,6 +101,12 @@ typedef volatile unsigned char	vu_char;
 #define _DEBUG	0
 #endif
 
+#ifdef CONFIG_SPL_BUILD
+#define _SPL_BUILD	1
+#else
+#define _SPL_BUILD	0
+#endif
+
 /* Define this at the top of a file to add a prefix to debug messages */
 #ifndef pr_fmt
 #define pr_fmt(fmt) fmt
@@ -121,6 +127,10 @@ typedef volatile unsigned char	vu_char;
 #define debug(fmt, args...)			\
 	debug_cond(_DEBUG, fmt, ##args)
 
+/* Show a message if not in SPL */
+#define warn_non_spl(fmt, args...)			\
+	debug_cond(!_SPL_BUILD, fmt, ##args)
+
 /*
  * An assertion is run-time check done in debug mode only. If DEBUG is not
  * defined then it is skipped. If DEBUG is defined and the assertion fails,