arm_adi_v5: make dap_lookup_cs_component() traverse subtables and handle multicore

When looking for a debug base address of a core, one should search
through all the ROM tables, not just the top-level one.

This code also assumes that the first found entry (in a depth-first
search) will correspond to core 0, the second to core 1 etc.

The patch is supposed to be an alternative implementation of
http://openocd.zylin.com/#/c/1313/.

Change-Id: Ifc88971a02fe3d9c00d9bf72a822ade5804d4e09
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1920
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>