sh: dreamcast: fix build failure from header reorg.

Oops, machvec.h is in asm/, it was previously removed due to overzealous
trimming. Fix up the path again.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/boards/dreamcast/setup.c

@@ -25,7 +25,7 @@
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <asm/rtc.h>
-#include <machvec.h>
+#include <asm/machvec.h>
 #include <mach/sysasic.h>
 
 extern struct hw_interrupt_type systemasic_int;