powerpc: Make some #includes explicit.

In preparation for merging processor.h, this adds some explicit
but won't be after the merge.

Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc/kernel/irq.c

@@ -57,6 +57,7 @@
 #include <asm/cache.h>
 #include <asm/prom.h>
 #include <asm/ptrace.h>
+#include <asm/machdep.h>
 
 #define NR_MASK_WORDS	((NR_IRQS + 31) / 32)
 

arch/ppc/kernel/pci.c

@@ -21,6 +21,7 @@
 #include <asm/byteorder.h>
 #include <asm/irq.h>
 #include <asm/uaccess.h>
+#include <asm/machdep.h>
 
 #undef DEBUG
 

arch/ppc/kernel/smp.c

@@ -34,6 +34,7 @@
 #include <asm/thread_info.h>
 #include <asm/tlbflush.h>
 #include <asm/xmon.h>
+#include <asm/machdep.h>
 
 volatile int smp_commenced;
 int smp_tb_synchronized;