Unify the arch headers.

The arch interface is defined in common headers and each arch has its
own implementation.

Change-Id: I2d783fcd951f2a51458d9c2d4adc5bf72200dde7
diff --git a/src/dlog.c b/src/dlog.c
index 9471cea..51ba6fb 100644
--- a/src/dlog.c
+++ b/src/dlog.c
@@ -19,7 +19,8 @@
 #include <stdbool.h>
 #include <stddef.h>
 
-#include "hf/arch.h"
+#include "hf/arch/console.h"
+
 #include "hf/spinlock.h"
 #include "hf/std.h"