This patch fixes a number of bugs caused by incomplete support for
non-existent registers. This is needed for targets that provide optional
registers or non-linear register numbers.
Change-Id: I216196e0051f28887a2c3da410959382369eed80
Signed-off-by: Steven Stallion <stallion@squareup.com>
Reviewed-on: http://openocd.zylin.com/4113
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>