target: restructure dap support

- add 'dap create' command to create dap instances
- move all dap subcmmand into the dap instance commands
- keep 'dap info' for convenience
- change all armv7 and armv8 targets to take a dap
  instance instead of a jtag chain position
- restructure tap/dap/target relations, jtag tap no
  longer references the dap, daps are now independently
  created and initialized.
- clean up swd connect
- re-initialize DAP also on JTAG errors (e.g. after reset,
  power cycle)
- update documentation
- update target files

Change-Id: I322cf3969b5407c25d1d3962f9d9b9bc1df067d9
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/4468
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

src/target/target.h

@@ -181,10 +181,15 @@ struct target {
 	bool halt_issued;					/* did we transition to halted state? */
 	int64_t halt_issued_time;			/* Note time when halt was issued */
 
+										/* ARM v7/v8 targets with ADIv5 interface */
 	bool dbgbase_set;					/* By default the debug base is not set */
 	uint32_t dbgbase;					/* Really a Cortex-A specific option, but there is no
 										 * system in place to support target specific options
 										 * currently. */
+	bool has_dap;						/* set to true if target has ADIv5 support */
+	bool dap_configured;				/* set to true if ADIv5 DAP is configured */
+	bool tap_configured;				/* set to true if JTAG tap has been configured
+										 * through -chain-position */
 
 	struct rtos *rtos;					/* Instance of Real Time Operating System support */
 	bool rtos_auto_detect;				/* A flag that indicates that the RTOS has been specified as "auto"