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/jtag/jtag.h

@@ -642,8 +642,6 @@ void jtag_poll_set_enabled(bool value);
  * level APIs that are used in inner loops. */
 #include <jtag/minidriver.h>
 
-bool transport_is_jtag(void);
-
 int jim_jtag_newtap(Jim_Interp *interp, int argc, Jim_Obj *const *argv);
 
 #endif /* OPENOCD_JTAG_JTAG_H */