x86: Fix build warning in arch/x86/mm/mmio-mod.c

Stephen Rothwell reported these warnings:

 arch/x86/mm/mmio-mod.c: In function 'print_pte':
 arch/x86/mm/mmio-mod.c:100: warning: too many arguments for format
 arch/x86/mm/mmio-mod.c:106: warning: too many arguments for format

The 'fmt' was left out accidentally.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus <torvalds@linux-foundation.org>
LKML-Reference: <1260775443.18538.16.camel@Joe-Laptop.home>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/mmio-mod.c

@@ -20,7 +20,7 @@
  * Derived from the read-mod example from relay-examples by Tom Zanussi.
  */
 
-#define pr_fmt(fmt) "mmiotrace: "
+#define pr_fmt(fmt) "mmiotrace: " fmt
 
 #define DEBUG 1