obmc-console: Fix bugprone-implicit-widening-of-multiplication-result

For example:

```
/usr/bin/clang-tidy -checks=-*, bugprone-implicit-widening-of-multiplication-result -export-fixes /tmp/tmpppty3tdm/tmpod_qxcie.yaml -p=build /mnt/host/andrew/home/andrew/src/openbmc/obmc-console/test/test-config-parse-logsize.c
../test/test-config-parse-logsize.c:24:11: error: performing an implicit widening conversion to type 'size_t' (aka 'unsigned long') of a multiplication performed in type 'int' [bugprone-implicit-widening-of-multiplication-result,-warnings-as-errors]
                { "4k", 4 * 1024, 0 },
                        ^
```

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I571983c6381fad7a14fb179108d14220f5dfdeca
diff --git a/log-handler.c b/log-handler.c
index 4e2425f..233f41f 100644
--- a/log-handler.c
+++ b/log-handler.c
@@ -43,7 +43,7 @@
 };
 
 static const char *default_filename = LOCALSTATEDIR "/log/obmc-console.log";
-static const size_t default_logsize = 16 * 1024;
+static const size_t default_logsize = 16ul * 1024ul;
 
 static struct log_handler *to_log_handler(struct handler *handler)
 {