Expose per arch headers.

Bug: 73013352

Test: Compiles.
Change-Id: Ic05660db7d7858a9857143ee5e58cdaddcf52a35
diff --git a/libunwindstack/RegsArm.cpp b/libunwindstack/RegsArm.cpp
index d05c3e2..7f16146 100644
--- a/libunwindstack/RegsArm.cpp
+++ b/libunwindstack/RegsArm.cpp
@@ -19,13 +19,12 @@
 #include <functional>
 
 #include <unwindstack/Elf.h>
+#include <unwindstack/MachineArm.h>
 #include <unwindstack/MapInfo.h>
 #include <unwindstack/Memory.h>
 #include <unwindstack/RegsArm.h>
-
-#include "MachineArm.h"
-#include "UcontextArm.h"
-#include "UserArm.h"
+#include <unwindstack/UcontextArm.h>
+#include <unwindstack/UserArm.h>
 
 namespace unwindstack {