printk: Add KBUILD_MODNAME and remove a redundant print prefix

Add KBUILD_MODNAME to make prints more clear.

Link: http://lkml.kernel.org/r/1538239553-81805-3-git-send-email-zhe.he@windriver.com
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: He Zhe <zhe.he@windriver.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>