Move interfaces to subdir

src/intf/mutex.cpp

@@ -1,4 +1,4 @@
-#include <sta/mutex.hpp>
+#include <sta/intf/mutex.hpp>
 
 
 namespace sta

src/intf/spi_device.cpp

@@ -1,4 +1,4 @@
-#include <sta/spi_device.hpp>
+#include <sta/intf/spi_device.hpp>
 
 #include <sta/assert.hpp>
 

src/intf/spi_interface.cpp

@@ -1,4 +1,4 @@
-#include <sta/spi_interface.hpp>
+#include <sta/intf/spi_interface.hpp>
 
 
 namespace sta

src/intf/uart.cpp

@@ -1,9 +1,9 @@
-#include <sta/uart.hpp>
+#include <sta/intf/uart.hpp>
 
 #include <sta/printf.hpp>
 
-#include <cstring>
 #include <cinttypes>
+#include <cstring>