transport: add transport_is_hla()

and move declaration of all transport_is_xxx() functions to transport.h

Change-Id: Ib229115b5017507b49655bc43b517ab6fb32f7a6
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4469
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

src/target/cortex_a.c

@@ -54,7 +54,7 @@
 #include "target_type.h"
 #include "arm_opcodes.h"
 #include "arm_semihosting.h"
-#include "jtag/swd.h"
+#include "transport/transport.h"
 #include <helper/time_support.h>
 
 static int cortex_a_poll(struct target *target);