dm: Disable dm_warn() in SPL

Since this function can use up quite a bit of space for its strings, disable
it by default in SPL. Use CONFIG_DM_WARN to re-enable it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>

include/config_defaults.h

@@ -21,6 +21,7 @@
 #define CONFIG_PARTITIONS 1
 
 #ifndef CONFIG_SPL_BUILD
+#define CONFIG_DM_WARN
 #define CONFIG_DM_DEVICE_REMOVE
 #define CONFIG_DM_STDIO
 #endif

include/dm/util.h

@@ -7,7 +7,13 @@
 #ifndef __DM_UTIL_H
 #define __DM_UTIL_H
 
+#ifdef CONFIG_DM_WARN
 void dm_warn(const char *fmt, ...);
+#else
+static inline void dm_warn(const char *fmt, ...)
+{
+}
+#endif
 
 #ifdef DEBUG
 void dm_dbg(const char *fmt, ...);