hw: move headers to include/

Many of these should be cleaned up with proper qdev-/QOM-ification.
Right now there are many catch-all headers in include/hw/ARCH depending
on cpu.h, and this makes it necessary to compile these files per-target.
However, fixing this does not belong in these patches.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/pxa2xx_timer.c b/hw/pxa2xx_timer.c
index c173fe4..8ea2416 100644
--- a/hw/pxa2xx_timer.c
+++ b/hw/pxa2xx_timer.c
@@ -10,7 +10,7 @@
 #include "hw/hw.h"
 #include "qemu/timer.h"
 #include "sysemu/sysemu.h"
-#include "hw/pxa.h"
+#include "hw/arm/pxa.h"
 #include "hw/sysbus.h"
 
 #define OSMR0	0x00