powerpc: Fix pseries (64-bit) build

A recent commit that removed rtas-fw.h and moved its contents to
include/asm-powerpc/rtas.h forgot to also remove the inclusion of
it in arch/powerpc/platforms/pseries/setup.c.

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

arch/powerpc/platforms/pseries/setup.c

@@ -67,8 +67,6 @@
 #include <asm/i8259.h>
 #include <asm/udbg.h>
 
-#include "rtas-fw.h"
-
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
 #else