ARM: ADIv5 JTAG symbol cleanup

ARM: ADIv5 JTAG symbol cleanup

Rename DAP_IR_* as JTAG_DP_* since those symbols are specifically
for JTAG-DP (or SWJ-DP in JTAG mode), and won't work with SWD.
Define the JTAG ABORT and IDCODE instructions for completeness;
add a comment about where to (someday) use ABORT.

Fix messaging which assumes everything is an SWJ-DP; say "JTAG-DP"
instead, it's at least more appropriate for all JTAG transports.

Shrink the affected lines.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>