Add abort when JTAG-DP transaction times out.

Fixes system hang for devices that don't ignore
transactions to bad addresses.

Change-Id: Ia98344d7efc12951ef79dbc82b8f792b70a22cee
Signed-off-by: Evan Hunter <ehunter@broadcom.com>
Reviewed-on: http://openocd.zylin.com/1115
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>