malloc_simple: Add logging of allocations

It is sometimes useful to see what memory is being allocated early during
boot. Add logging to support this, using a new LOGC_ALLOC category.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/log.h b/include/log.h
index c88a1b5..0f2bc19 100644
--- a/include/log.h
+++ b/include/log.h
@@ -114,7 +114,7 @@
 /* Emit a log record if the level is less that the maximum */
 #define log(_cat, _level, _fmt, _args...) ({ \
 	int _l = _level; \
-	if (_l <= _LOG_MAX_LEVEL) \
+	if (CONFIG_IS_ENABLED(LOG) && _l <= _LOG_MAX_LEVEL) \
 		_log((enum log_category_t)(_cat), _l, __FILE__, __LINE__, \
 		      __func__, \
 		      pr_fmt(_fmt), ##_args); \