icepick-d: extend access to core control register

icepick-d: extend access to core control register

The ICEPick-D jtag router has core control registers
that provide the same (or similar) functionality as
the tap control register, for individual cores
accessible through the same tap (e.g. through a DAP).

Core control registers are located at address "0x60 +
core-id" of the ROUTER address space (IR=ROUTER).

It is sometimes helpful or even necessary to modify the
core control register. This patch renames the
"icepick_d_coreid" function to the more appropriate
"icepick_d_core_control" and adds a "value" argument
that allows writing of arbitrary value.
"icepick_d_tapenable" is extended by an optional value
argument so that core control can be written as the tap
is enabled.

Change-Id: I0e7f91b596cb5075364c6c233348508f58e0a901
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/4141
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>