cortex: Set default memaccess_tck only during examine

It's currently set during target creation but the AP that will be used
for the target is not even known.

Change-Id: I4502e7eb1fa8d90f746445b8cf8a4c21cb7d519e
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/3155
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>

src/target/cortex_m.c

@@ -2122,9 +2122,6 @@ static int cortex_m_init_arch_info(struct target *target,
 
 	armv7m->arm.dap = tap->dap;
 
-	/* Leave (only) generic DAP stuff for debugport_init(); */
-	tap->dap->ap[dap_ap_get_select(tap->dap)].memaccess_tck = 8;
-
 	/* register arch-specific functions */
 	armv7m->examine_debug_reason = cortex_m_examine_debug_reason;