[POWERPC] Include udbg.h when using udbg_printf

This fixes the error
	error: implicit declaration of function "udbg_printf"

We have a few spots where we reference udbg_printf() without #including
udbg.h.  These are within #ifdef DEBUG blocks, so unnoticed until we do
a #define DEBUG or #define DEBUG_LOW nearby.
Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/hash_utils_64.c

@@ -51,6 +51,7 @@
 #include <asm/cputable.h>
 #include <asm/sections.h>
 #include <asm/spu.h>
+#include <asm/udbg.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)

arch/powerpc/mm/slb.c

@@ -25,6 +25,7 @@
 #include <asm/smp.h>
 #include <asm/firmware.h>
 #include <linux/compiler.h>
+#include <asm/udbg.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)

arch/powerpc/platforms/cell/smp.c

@@ -44,6 +44,7 @@
 #include <asm/rtas.h>
 
 #include "interrupt.h"
+#include <asm/udbg.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)

arch/powerpc/platforms/pseries/firmware.c

@@ -25,6 +25,7 @@
 
 #include <asm/firmware.h>
 #include <asm/prom.h>
+#include <asm/udbg.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)