Added missing uart file.

conts/baremetal/uart_service/include/uart.h

@@ -0,0 +1,17 @@
+
+#ifndef __UART_SERVICE_H__
+#define __UART_SERVICE_H__
+
+#include <l4/api/capability.h>
+#include <l4/generic/cap-types.h>
+
+/*
+ * uart structure ecapsulating
+ * capability and virtual base address of uart
+ */
+struct uart {
+	unsigned long base; /* VMA where uart will be mapped */
+	struct capability cap;  /* Capability describing uart */
+};
+
+#endif /* __UART_SERVICE_H__ */