hv:move down the structure intr_source

Now the structures(union source & struct intr_source) are defined
in ptdev.h,they are used in vtd.c and assign.c,
vtd is the hardware layer and ptdev is the upper-layer module
from the modularization perspective, this patch move down
these structures to avoid reversed dependency.

Tracked-On: #1842
Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/vtd.c

@@ -17,6 +17,7 @@
 #include <mmu.h>
 #include <lapic.h>
 #include <vtd.h>
+#include <timer.h>
 #include <logmsg.h>
 #include <vm_configurations.h>