Compile msi.cpp for x86_64.

Needed to link the PCI module, not enabling it yet though, I'm not
sure whether everything needed for it is in place yet.

src/system/kernel/arch/x86/Jamfile

@@ -54,7 +54,6 @@ if $(TARGET_ARCH) = x86_64 {
 		arch_user_debugger.cpp
 		ioapic.cpp
 		irq_routing_table.cpp
-		msi.cpp
 		syscall.S
 		x86_signals.cpp
 		x86_signals_asm.S
@@ -90,6 +89,7 @@ local archGenericSources =
 	arch_vm.cpp
 	arch_vm_translation_map.cpp
 	apic.cpp
+	msi.cpp
 	pic.cpp
 
 	# paging

src/system/kernel/arch/x86/arch_int.cpp

@@ -237,8 +237,8 @@ arch_int_init_io(kernel_args* args)
 	// TODO x86_64
 #ifndef __x86_64__
 	ioapic_init(args);
-	msi_init();
 #endif
+	msi_init();
 	return B_OK;
 }
 

src/system/kernel/arch/x86/msi.cpp

@@ -17,6 +17,10 @@ static bool sMSISupported = false;
 void
 msi_init()
 {
+#ifdef __x86_64__
+	// TODO x86_64.
+	return;
+#endif
 	if (!apic_available()) {
 		dprintf("disabling msi due to missing apic\n");
 		return;