ARM: compile fix for DEBUG_LL=y && MMU=n

debug_ll_addr is only used on machines with an MMU so it can be #ifdef'ed
out safely. This fixes:

arch/arm/kernel/debug.S: Assembler messages:
arch/arm/kernel/debug.S:104: Error: too many positional arguments

The problem was introduced in e5c5f2ad ARM: implement debug_ll_io_init().
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NOlof Johansson <olof@lixom.net>

arch/arm/kernel/debug.S

@@ -100,12 +100,14 @@ ENTRY(printch)
 		b	1b
 ENDPROC(printch)
 
+#ifdef CONFIG_MMU
 ENTRY(debug_ll_addr)
 		addruart r2, r3, ip
 		str	r2, [r0]
 		str	r3, [r1]
 		mov	pc, lr
 ENDPROC(debug_ll_addr)
+#endif
 
 #else