arm_adi_v5: Clean up dap info command

arm_adi_v5: Clean up dap info command

Reduce use of magic numbers and add AXI type MEM-AP detection. Don't try
to call dap_rom_display on a non-existent AP.

AP identification is unique per designer, so make sure the JEDEC code
matches ARM when interpreting the AP type.

Change-Id: I8e86b7de61811382afe99bf15094ab71b43f5fdf
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/3150
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>