Add file needed for rpl border router

cpu/native/dev/uart1.h

@@ -0,0 +1,31 @@
+/*
+  Copied from mc1322x/dev/cpu. 
+  
+  This file exists as a work-around for the hardware dependant calls
+  to slip_arch_init.
+
+  Current the prototype for slip_arch_init is slip_arch_init(urb)
+
+  and a typical call is something like
+  slip_arch_init(BAUD2URB(115200))
+
+  BAUD2UBR is hardware specific, however. Furthermore, for the sky
+  platform it's typically defined with #include "dev/uart1.h" (see
+  rpl-boarder-router/slip-bridge.c), a sky specific file. dev/uart1.h
+  includes msp430.h which includes the sky contiki-conf.h which
+  defines BAUD2UBR.
+
+  To me, the correct think to pass is simply the baudrate and have the
+  hardware specific conversion happen inside slip_arch_init. 
+
+  Notably, most implementations just ignore the passed parameter
+  anyway. (except AVR)
+  
+ */
+
+#ifndef DEV_UART1_H
+#define DEV_UART1_H
+
+#define BAUD2UBR(x) x
+
+#endif