Relax polling check if not in JTAG mode

Polling was disabled based on global variables jtag_trst and jtag_srst
which were never touched in non-JTAG mode. Modify the check and remove
the ugly workaround to avoid calls to a possibly uninitialized JTAG
subsystem.

Change-Id: I3b18c81e0fba7aaf35afe6f08c3fe8fa6f8443fd
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2143
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

src/jtag/core.c

@@ -166,6 +166,9 @@ bool is_jtag_poll_safe(void)
 	 * It is also implicitly disabled while TRST is active and
 	 * while SRST is gating the JTAG clock.
 	 */
+	if (!transport_is_jtag())
+		return jtag_poll;
+
 	if (!jtag_poll || jtag_trst != 0)
 		return false;
 	return jtag_srst == 0 || (jtag_reset_config & RESET_SRST_NO_GATING);

src/target/adi_v5_swd.c

@@ -429,9 +429,6 @@ static int swd_init(struct command_context *ctx)
 	if (status == ERROR_OK)
 		LOG_INFO("SWD IDCODE %#8.8" PRIx32, idcode);
 
-	/* this is a workaround to get polling working */
-	jtag_add_reset(0, 0);
-
 	return status;
 }