kernel/smp: Define pr_fmt() for smp.c

This makes all our pr_xxx()'s start with "smp: ", which helps pin down
where they come from and generally looks nice. There is actually only
one pr_xxx() use in smp.c at the moment, but we will add some more in
the next commit.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: akpm@osdl.org
Cc: jgross@suse.com
Cc: ak@linux.intel.com
Cc: tim.c.chen@linux.intel.com
Cc: len.brown@intel.com
Cc: peterz@infradead.org
Cc: richard@nod.at
Cc: jolsa@redhat.com
Cc: boris.ostrovsky@oracle.com
Cc: mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1477460275-8266-1-git-send-email-mpe@ellerman.id.auSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/smp.c

@@ -3,6 +3,9 @@
  *
  * (C) Jens Axboe <jens.axboe@oracle.com> 2008
  */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/irq_work.h>
 #include <linux/rcupdate.h>
 #include <linux/rculist.h>