[POWERPC] Add include of linux/of.h to numa.c

numa.c requires routines declared in linux/of.h, so should include it.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/mm/numa.c

@@ -18,6 +18,7 @@
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/lmb.h>
+#include <linux/of.h>
 #include <asm/sparsemem.h>
 #include <asm/prom.h>
 #include <asm/system.h>