[POWERPC] ppc: More compile fixes

This fixes a few more miscellaneous compile problems with ARCH=ppc.

1. Don't compile devres.c on ARCH=ppc, it doesn't have ioremap_flags.
2. Include <asm/irq.h> in setup.c for the __DO_IRQ_CANON definition.
3. Include <linux/proc_fs.h> in residual.c for the
   definition of create_proc_read_entry.
4. Fix xchg_ptr to be a static inline to eliminate a compiler warning.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/ppc/kernel/setup.c b/arch/ppc/kernel/setup.c
index bfddfde..51e8094 100644
--- a/arch/ppc/kernel/setup.c
+++ b/arch/ppc/kernel/setup.c
@@ -36,6 +36,7 @@
 #include <asm/nvram.h>
 #include <asm/xmon.h>
 #include <asm/ocp.h>
+#include <asm/irq.h>
 
 #define USES_PPC_SYS (defined(CONFIG_MPC10X_BRIDGE) || defined(CONFIG_8260) || \
 		      defined(CONFIG_PPC_MPC52xx))