EJTAG v2.0 indicated some debug caps in IMP register.
V2.6 moved them to DCR register. To make it more universal,
convert this values and store them for later use.
Change-Id: Id6b9f47c9c2ea94d37281ebfcae5acf357261ddf
Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Reviewed-on: http://openocd.zylin.com/1932
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>