testmmiotrace.c: Add and use pr_fmt(fmt)

- Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt.
- Strip MODULE_NAME from pr_<level>s.
- Remove MODULE_NAME definition.

Signed-off-by: Joe Perches <joe@perches.com>
LKML-Reference: <3bb66cc7f85f77b9416902e1be7076f7e3f4ad48.1254701151.git.joe@perches.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>