Move arch specific fiels to arch subdir

Take the chance to update some includes using files available in that
subdir to have them ina more uniform way.

Change-Id: Ibda3c54fd4dc3f6b845cc373f1a1e6b758c1ea82
diff --git a/Transceiver52M/Synthesis.cpp b/Transceiver52M/Synthesis.cpp
index 22481d5..262c638 100644
--- a/Transceiver52M/Synthesis.cpp
+++ b/Transceiver52M/Synthesis.cpp
@@ -29,8 +29,8 @@
 #include "Synthesis.h"
 
 extern "C" {
-#include "common/fft.h"
-#include "common/convolve.h"
+#include "fft.h"
+#include "convolve.h"
 }
 
 static void interleave(float **in, size_t ilen,