Don't include cpu.h in timer.h

Change the name of the define used to indicate SVGA multi-monitor-capable cards

src/machine/m_at_socket5.c

@@ -29,6 +29,7 @@
 #include <86box/fdc_ext.h>
 #include <86box/hdc.h>
 #include <86box/hdc_ide.h>
+#include "cpu.h"
 #include <86box/timer.h>
 #include <86box/fdd.h>
 #include <86box/fdc.h>

src/machine/m_xt_olivetti.c

@@ -30,6 +30,7 @@
 #include <wchar.h>
 #define HAVE_STDARG_H
 #include <86box/86box.h>
+#include "cpu.h"
 #include <86box/timer.h>
 #include <86box/io.h>
 #include <86box/pic.h>

src/machine/m_xt_philips.c

@@ -23,6 +23,7 @@
 #define HAVE_STDARG_H
 #include <86box/86box.h>
 #include <86box/nmi.h>
+#include "cpu.h"
 #include <86box/timer.h>
 #include <86box/pit.h>
 #include <86box/mem.h>